What's going on with the rubber

[JohnU]

Some grayish white residual substance appeared on the tires of unbuilt revell 69 Dodge Charger R/T. It seems to wipe off easy with no damage but wondering what could be causing it? I'm storing the kit in a dry basement with the rest of my collection. This seems to be the only one I've found like this and have never seen this before. Should I be concerned?

[espo]

Some "rubber" used by kit makers in the past have had this problem. There has been a discussion about it here in the past, but I don't think anyone has a 100% answer. The tires that I had this problem with cleaned up just fine with a mild dish soap and water then wiped dry. Problem didn't return.  

[Don Sikora II]

This seems most common with AMT tires froth late Sixties/early Seventies. Not sure what's causing it, but it could be mold release residue from when the tires were molded.

[Snake45]

I'm working on a resto that had white residue on the sidewalls of the tires (old skinny Firestones, not the common Firestone Supremes). Dish soap didn't take it off, nor did Windex, nor did rubbing alcohol. Was about to try leather saddle soap, and then Armorall, but while looking for the Armorall, I found my wife's Shout stain remover, and tried that. It seems to have worked. 

If the tires aren't still black tomorrow, I'll let you know. 

Just realized I hadn't tried Goo Gone yet. Or Hoppes #9. 

[peteski]

Naphtha (Ronsonol lighter fluid, or VM&P Naphtha from a hardware store) usually work well for this.

[Art Anderson]

On 8/14/2017 at 1:33 PM, Don Sikora II said:

This seems most common with AMT tires froth late Sixties/early Seventies. Not sure what's causing it, but it could be mold release residue from when the tires were molded.

Interesting, that given my once-frequent visits to AMT's Maple Road plant,  their PVC (NOT RUBBER, BTW, save for their Authentic Model Turnpike cars, which had molded rubber tires for traction), every time I walked past their injection-molder that produced a constant stream of tires, never once did I see anyone use any mold release with that tooling--in fact, the machine was set to a relatively fast cycle, with a fresh batch of tires being popped every 2-3 minutes or so, with nary anyone even monitoring--like it was on "automatic pilot".  That almost "oily" stuff that leached out of many of those older tires back then, was PVC Monomer,  which use became severely reduced with the great PVC-Monomer "Cancer" scare of 1976-77.

Art