On this particular piece, I used Mig's grease & oil solution. It's a solution that MIG has that you can purchase for models. I used the vaseline to give it the little extra thickness.
Working on this diorama has been a pleasure. Trying new weathering techniques have also yielded good results without spending am arm or a leg on many weathering solutions( although, they help beginners). Hope you all like the results of this build.