I took keg plugs made from wood about 2 inches in diameter from a brew contact who had a few hundred left over after kegs changed. They used to drive one of these in middle of keg to identify brew inside back in the 70's I joined then with dowling so each keg sits on its own stand. I use a sponge left in keezer to get any moisture in low spot and kegs sit above any moisture so spills if any are easy to mop up.