I've been using mini freezer blocks, but leaving them out for a bit before I give them to the hamsters. I've found trainer socks are good to put them in. new trainer socks I should add and cheap ones from woolworths, and plain cotton only. non of my hamsters have tried to eat the sock.
I have colling tiles as well, but the robos tend to put woodshavings all over them.
It's been really hot in my house 30degree in my room and thats colder than outside
, windows wide open and curtains closed.
it's time to buy a fan I think.