Try simple greenIf they are rubberized plastic, sadly there isn't a lot you can do if they go sticky.... Age and contact with oil make them turn to poo, they get sticky and gooey, nothing can save it. I wonder if you can paint them with something to incase it so you have a hard outer shell?
When new they feel great on things like screw drivers, give it a few years and then they go tacky and fall apart.
I tried a few different cleaners, purple power, green, blue and yellow. The handles are very clean now, but the coating is still just as sticky. I did notice several wear points on the handles. The coating is fairly thick. Maybe worst case I can scrape it all off and have just the plastic. I talked to a CAT parts person today. They are going to order in both handles and see what they look like. He said they are solid plastic. Maybe CAT has decided not to put the coating on the newer handles. Anyway, he also said he would look into getting CAT corporate to allow him to take a chunk off the price for the new ones. I love this machine, just a couple minor inconveniences to work around. The cab is pressurized and the air conditioning works great now that I have really cleaned all the components. It does get a lot of dirt in the system if neglected.Try simple green