Any suggestions please for best lubrication for the bearings for an ms optical trackball mouse. I bought a number for my office and all are sticky to use for very fine computer work. I contacted the manufacturer and their answer was to take the model out of production. This is my very favourite trackball as it has scroll wheel as well as four programmable buttons so I have persisted in trying to find the right lubricant. The bearings are metal set in moulded plastic.
I have tried just cleaning thoroughly with video head cleaner, although they are all new and not dirty. I then tried thin mineral oil, ptfe spray, switch cleaning lubricant and silicone grease. The silicone works best but the balls still stick at crucial moments instead of moving freely.
Any suggestions gratefully received.
Many thanks

After a good cleaning of the cavity...A WEE bit of Petroleum jelly.

try thin silicon oil (not grease). Works excellent on my slide-cellular phone..

get it from Dow corning- silicon spray

many thanks for all the helpful suggestions