[dude_500]

Does anyone know what the material typically used as the foam in headphone earpads is, or where to buy it? Replacement pads themselves are all over the place, but I want a chunk of the foam to cut my own earpads, and google searches have not yielded anyone selling that. So I guess I need to know the name of the foam used to search that way. 
 
I ordered "polyurethane 1 psi (extra soft)" from McMaster, and it is many many times firmer than the foam in my HD600 headphones.

 

[chinsettawong]

Try the sponge for car wash.  It's cheap and good. 
 
Wachara C.

 

[Nuuna]

Memoryfoam.

 

[earfanatic]

Memoryfoam 2x.
If You can not source it, wou can buy Memoryfoam pillow in IKEA.