What about submerging it in mineral oil?

A more whimsical method is to put the thing in a glass of water with the cord sticking out. :-)

https://www.reddit.com/r/EmulationOnAndroid/comments/1m269k0...

You can buy a liquid cooled tablet.

https://onexplayerstore.com/products/onexplayer-super-x?vari...

I have a small portable fan that I place under it basically any time I use it for any development work. It gets thermally throttled pretty fast otherwise. It's definitely the wrong machine for my needs but it's what I gotta work with for now.