Should a piper put cork grease on the cork pad of a chanter key? What if the pad is made of felt instead of cork?
Most diffentily !If the pads are felt then you use felt grease .which you can pick up in any felt grease shop!
Cork Grease is typically for cork joints in a woodwind. The cork pads I’ve seen wore out very quickly if they ever worked very well at all. I’d personally convert over to the traditional leather, or as some makers are using a modern foam rubber. If the maker affixed the pad to the key in a traditional manner (i.e. sealing wax), it’s easy to remove the old, and relatively easy to install the new.
Dionys
Whoa, whoa, whoa… Are you talking about a pad as in an actual keypad or just a bit of cork on the end of the key to keep it from striking the wood? In any case, don’t put cork grease on the cork. Cork grease is meant for cork-lapped tenons and other things that, unlike most uilleann pipers, get a lot of action. Overuse of it though will cause the cork to deteriorate and fall off. 
I agree. If you must use something to keep the cork from sticking, you should use Kerry grease.
djm
Man!! County Kerry never gets a break…which is as it should be 
You guys are killing me !!! : )