Q:

How to get cats to stop eating sound proofing material

I have sound proofing/deadening material up on my walls to help acoustics, but our cats like to eat it some times, and I can't imagine that's good for them.
Is there something we could make/get to spray on the foam that would deter the cats from eating it? They do this when no one is home/sleeping, etc. so we can't be there all the time to physically stop them. 
Obviously taking the foam down off the walls is one option, but it would be nice to keep it up and stop them from eating it if at all possible. 

A:

You could try using a citrus-based "cat repellent" type spray. You can either buy a ready made one or mix one up at home. Cats hate the scent of citrus so they will generally avoid the area but it's not harmful to them.
You'll want to test any such spray on a discreet area of the foam first obviously to make sure that it doesn't stain the foam as I'm guessing that wouldn't be a good look!

