I've got a tractor parked in the shed. So, always have a good supply of diesel fuel handy. My technique includes diesel, several clean 1 gal & 1 qt paint cans, kitty litter trays, elbow length nitrile gloves, wire brushes, shop rags. I completely disassemble bike. Roll up chain & place on bottom of 1 gal paint can. Put freewheel on top of chain. Toss in the FD & RD, both brakes, bottom bracket. You can fit everything in a one gallon can with the exception of the crank arms & chainrings. Pour enough diesel into can to cover everything. Put lid on hammer tight. Then, shake the the can vigorously. Let it soak overnight. Shake, soak, repeat, etc. Sometimes I soak stuff for several weeks while waiting for new tires & other parts to arrive. Eventually, I put on big nitrile gloves & fish everything out. Wire brush everything over a kitty litter tray. After I get the freewheel clean I'll soak it in automatic transmission fluid. Oh yeah. I've brought several very nice old Suntour freewheels back to life this way.