I have picked up a few 1950s FLINT US Stainless Steel Utensils lately. Decades of constant washing and drying and exposure to the minerals causes plastic handles to roughen up and look beaten. This type of plastic is pretty indestructible otherwise. The rough surface can be sanded smooth or even burnished with steel wool and rubbing compound to remove the worst of the texture. Plastic Automotive trim polish will remove mineral residue and return the original finish to the handle. As long as it isn’t submitted to another decade of dishwasher exposure it should stay that color. If it should get dull again, a wipe with Armor-All will renew it.