Crate bedding/padding in the summer?

What do you use as bedding/padding in your crates during the summer?

We try to keep the house as cool as possible without using the AC while we're gone, but I think Smiley probably gets pretty hot with his comforter in there. I'm just not sure what else to use that will stay cool but give him something comfy to lie on.

I just leave their blankets in there, mine are pretty good at shoving aside things they don't want lol.

Right now, Feist has nothing in there. If there is anything, she just crawls under it to get to the cooler crate pan, so I don't bother.

I have cooling crate mats.