I've removed freewheels like this by disassembling them and then holding the freewheel body on a vise, but with a strip of thick leather around the body to prevent damage. The freewheel can be reassembled later using a thong made with a bent spoke with tips flattened to hold the pawls.
Many would think it's a waste of time (about 20 mins) on a cheap part, but I hate throwing off a perfectly reusable item just because one's lazy.