Quoted from woz:I keep them nice and dry. Eventually the grease will just gum up with dust and crap and it won't work properly. Polish the cups and they'll be nice and slippery anyway.
This is what I do and have never had a problem, but everyone has their way of doing it. As far as any wear caused without grease added there would be none. You have metal to plastic. The general rule for lubrication in pinball machines is metal to metal only. I think it was overkill by the manufacture to make it a rule of thumb to lubricate the Pop Bumper Spoon to begin with. To me lubrication would only cause you grief in the long run as it will just do the same thing again that you are already dealing with, a gummed up part.
Ken
