Recently I saw in another website by the name of Drum chat some one looking to restore the white plastic on Rogers timbales Rims. Yet No one knew the correct answer to a simple problem. As a long time member of Vintage Drum form and a master of the craft here I have the response for any of our members if they are going through similar problem and want to restore.
The product to do such is called liquid rubber sealant . It comes in different colors and you just have to dip the rims in this liquid and let it dry. Then sand the excess off and your rims are like new again. It also can be used on tools for a more sturdy grip.