Just replaced targets on an early Stern, Cosmic Princess. Like Nine Ball, it has coils that drop the targets. A few of the targets are now sticking on the way down on the switch. I cleaned up all the mechs, including grease on said switch. Do i need to put grease back on this, or shave the area where the drop target makes contact? Any other recommendations?

I'll be replacing targets on my mate's Nine ball and anticipate similar problems.