There is a lot of different points of view regarding the coffee grounds.
personally I've never had problem, living in south Florida with no AC room. but after enjoy the coffee I dry it very well. after 6 years, knocking wood I never suffer any kind of infestation product of the coffee use.
Now is that when you use it on the layout or just in general?
I have to worry that if you use it on the layout that it would make a lousy cup of coffee..........
I used coffee in my layout for 5 years until I remove everything an install 2 rails track.
when I remove it the coffee was intact, no sign of any decomposition.
so was not luck, regarding your signature.
Ag