Help with cleaning 1/25 promo, large diecast collection

[mikemich]

Hi,  back after a few years!  I have a few hundred diecasts - original issue Corgi, Dinky, Matchbox - and a promo car collection which was my dad's - and although they were stored in enclosed glass display cases, many suffered from oxidation.  My mom passed away recently and I'll be needing to move the collection to my own house.  I'm looking to ultimately keep and continue displaying some of these, photo-catalogue each piece and probably sell a number of them.  I'm trying to decide A) how to clean them, to the extent they can be restored, and then how to best research for accurate pricing.  This project sadly has been neglected as I didn't have the necessary time to devote to this due to life in general... but now I am basically semi-retired and looking to focus on working on this.  

Because of imperfect humidity environment, many of the  Jo-Han cars in the 1/25, 1/24 collection have oxidation residue.  I've got a sampling of some of the worst in the attached photos; tho they aren't extreme close-up.  If there's any sort of best practices or protocol for dealing with this embedded dust, I'd really appreciate any advice...as well as suggestions on how to move forward on appraisal of this collection.  I started macro-photographing most of the smaller scale diecasts and now am looking to finish those and shoot the larger scales,  as I figure that's probably the first step to getting the entire lot of the collection properly evaluated.   I know there's many different ways to go as far as appraisal and selling.  My brother has a friend who is an online auctioneer who has regular vintage toys/cars among all the other categories of collectibles...but I'm more interested in connecting with people who specialize specifically in diecasts and promo cars.  Would be glad to get any recommendations as far as that goes, as well.  Thanks for your time reading through all of this!  : )  Mike in Detroit

[Snake45]

I'd start with a mix of dishwashing liquid in warm water, applied/scrubbed with a toothbrush. I'd be surprised if that didn't take care of most if not all of it. If not, I'd move up to rubbing alcohol. 

Whatever you do, don't used ammonia or anything with ammonia in it, such as Windex or other window cleaner, as this can damage or strip the chrome. 

The interiors (including the insides of the glass) on closed cars will be your biggest problem, as there's no good way to clean them out without disassembling the model. Promo disassembly isn't easy in the case of some JoHans, where they used those one-way screws. 

Good luck and let us know how it goes. 

[64Comet404]

The easiest solution for cleaning is to wash the promos in water with a bit of dish soap, and rinse afterwards. A soft toothbrush is good for removing some of the dirt However, the oxidized chrome is what it is. Some metallized surfaces do degrade over time. The die-casts are a different issue, since many of these were cast from an unstable alloy. They can be cleaned, but there's no certain method of fixing them without destroying their value. 

[mikemich]

17 minutes ago, Snake45 said:

I'd start with a mix of dishwashing liquid in warm water, applied/scrubbed with a toothbrush. I'd be surprised if that didn't take care of most if not all of it. If not, I'd move up to rubbing alcohol. 

..., don't used ammonia or anything with ammonia in it, such as Windex or other window cleaner, as this can damage or strip the chrome. 

Thanks!  Great advice. I found some of my notes from when I started on this a few years ago and a couple of bottles of Novus plastic polish that I didn't know I had.  Not sure if you're familiar with this product but I think your method makes the most sense to start with.  Will keep in touch and post some photos as I get further into this- hopefully will have some good  'before and after' results to share : )  Thanks again,  Mike

[Tom Geiger]

I’ll differ a bit. Don’t clean them!  The best place to sell would be on eBay in the promo category.  Some collectors would rather clean them themselves. 

And as already said, there’s nothing you can do with oxidizing chromed, nor warped bodies like the Lincoln or Buick. The warp isn’t due to your dad storing them incorrectly, it’s a bad characteristic if the plastic mix used back then and probably warped within a few years if it’s manufacture. You won’t see this past the early 1960s as each manufacturer got smart and went to a better plastic. 

If indeed you are going to clean them, as said don’t use any chemicals harsher than dishwashing soap. Use Q-tips to reach inside interiors. And be very careful of small parts like steering wheels, shifters and ornaments like the hood ornament on your Lincoln. They are already broken on a lot of the ones I’ve seen.  

Edited December 27, 2020 by Tom Geiger

[mikemich]

16 minutes ago, 64Comet404 said:

The easiest solution for cleaning is to wash the promos in water with a bit of dish soap, and rinse afterwards. A soft toothbrush is good for removing some of the dirt However, the oxidized chrome is what it is. Some metallized surfaces do degrade over time. The die-casts are a different issue, since many of these were cast from an unstable alloy. They can be cleaned, but there's no certain method of fixing them without destroying their value. 

Great! Thanks. Yeah I think some of my die-casts are a little too far gone as far as the oxidation - had moderately good success in eliminating the surface crud similar to that in the photo on the resin models - but in most cases some residual 'age spots' remained on the painted surfaces... as you say, it is what it is; )

Mike

[mikemich]

7 minutes ago, Tom Geiger said:

I’ll differ a bit. Don’t clean them!  The best place to sell would be on eBay in the promo category.  Some collectors would rather clean them themselves. 

And as already said, there’s nothing you can do with oxidizing chromed, nor warped bodies like the Lincoln or Buick. The warp isn’t due to your dad storing them incorrectly, it’s a bad characteristic if the plastic mix used back then and probably warped within a few years if it’s manufacture. You won’t see this past the early 1960s as each manufacturer got smart and went to a better plastic. 

If indeed you are going to clean them, as said don’t use any chemicals harsher than dishwashing soap. Use Q-tips to reach inside interiors. And be very careful of small parts like steering wheels, shifters and ornaments like the hood ornament on your Lincoln. They are already broken on a lot of the ones I’ve seen.  

Thanks Tom.  That is an interesting point to consider, i.e., just leaving 'as-is.'   Part of me can't resist wanting to lift off some of the more extreme 'crud' - but i know when i've tested this there's likely going to be a faded area left on the painted surface area where it was removed.  I did know a little about the "Johan curve" that people have called that warping effect so i know there's little I can do about that and i would think serious collectors should factor that in when considering price.

[Snake45]

30 minutes ago, mikemich said:

I...a couple of bottles of Novus plastic polish that I didn't know I had.  Not sure if you're familiar with this product ...

That's not really for cleaning, which is your problem right now. That's for if you want to get a spectacular shine on some clean, colored plastic. It takes some skill and some work but the results can be spectacular--almost rivaling a really good paint job. 

That blue AMT '66 Mercury should clean up VERY nicely, if there's no damage or missing parts not seen in the pic. It should come apart fairly easily. Unfortunately it's not super-rare or super-valuable, as the full-detail kit is still in current production, but it would still make a great display piece and addition to any promo collection. If it were the '66 Comet Cyclone, THAT would be VERY desirable and valuable! 

[mikemich]

42 minutes ago, Snake45 said:

That's not really for cleaning, which is your problem right now. That's for if you want to get a spectacular shine on some clean, colored plastic. It takes some skill and some work but the results can be spectacular--almost rivaling a really good paint job. 

That blue AMT '66 Mercury should clean up VERY nicely, if there's no damage or missing parts not seen in the pic. It should come apart fairly easily. Unfortunately it's not super-rare or super-valuable, as the full-detail kit is still in current production, but it would still make a great display piece and addition to any promo collection. If it were the '66 Comet Cyclone, THAT would be VERY desirable and valuable! 

Cool, thanks!  I'd love to get opinions on what else I have.  Have not  been on the forums in awhile so I need to look around but I assume it's ok to post my entire collection in the photo gallery section even if they're just about all promos- and not kit cars.  Thinking about just staging and shooting each one individually in "as-is" condition for now.

[wrenchr]

I'd soak in the warm dishsoap water and then wrap in paper towel to dry. If you disassemble and parts are not painted or plated I've used purple power to soak in.    

[ChrisBcritter]

2 hours ago, mikemich said:

Cool, thanks!  I'd love to get opinions on what else I have.  Have not  been on the forums in awhile so I need to look around but I assume it's ok to post my entire collection in the photo gallery section even if they're just about all promos- and not kit cars.  Thinking about just staging and shooting each one individually in "as-is" condition for now.

Please do! You have some good stuff in there - I'd love to have the Cruver '49 Olds 98 and the Jo-Han '69 Coupe deVille if I had a spare kidney to sell .

[Motor City]

Mike,

Do not use alcohol as it could react with the windows and body plastic.  Do not use a toothbrush either unless it is EXTREMELY soft, or you'll scratch the surfaces.  Your best bet is to use a mild liquid soap and wash the outside of the car with a wet paper towel.  On the inside, squirt a small amount of glass cleaner on the dashboard, seats, package tray and floors, clean everything with long cotton swabs, then thoroughly rinse it out in warm (not hot) water.  Also use a paper towel with liquid soap to gently clean the chrome, wheels and tires.  Rinse everything off in lukewarm water.  Then use an electric duster to blow everything dry.  You can buy one for about $100 as follows:

Amazon.com: Metro ED500 DataVac 500-Watt 120 volt 0.75-HP Electric Blower Duster: Office Products