Restoration of Tamiya cars
So long as there are no tears in rubber pieces, they can be cleaned up quite nicely. I suggest soaking them in a warm soapy water solution for about 30 minutes, this loosens any caked on dirt or oil. Then gently scrub the item with a soft used toothbrush. I find that for really greasy items it helps to dip the head of the toothbrush directly into liquid dish soap prior to scrubbing. The highly concentrated dish soap serves to instantly emulsify the greasy on the rubber as you’re scrubbing it. Otherwise, you’ll find that you’re just moving the grease from one section of the rubber piece to another.
Again, low-gloss Armor All will restore a dark nature black color to these pieces. Regular Armor All tends to give rubber a false high-gloss finish which looks really tacky.