If you are having a problem with gray squirrels eating more than their share of suet, here is something you might want to try. Typically, squirrels prefer eating suet laced with peanut butter and peanuts. If this is the case in your backyard, simply replace the peanut butter suet with plain suet. While birds will eat it, it seems that bushytails are not particularly fond of plain suet. While this solution might not work in all backyards, this simple, inexpensive approach to this problem just might work for you.
I make my own suet with PB and lard and dry ingredients. I add cayenne pepper and hot pepper flakes to the mixture. So far the squirrels leave it alone.
Only thing that ever worked in our yard was the hot suet, but it only worked for a few months until the squirrels got used to the red pepper.