Muratic acid is a cheap, available, effective and slightly dangerous rust
remover for small parts. It is sold is hardware stores for swimming pool
and concrete cleaning. Wear protective clothing. Use a plastic container.
Use diluted muratic acid. Pour in the water first, then add the acid, then
dunk in the parts. Store in a safe manner. Do not store near ANYTHING that will rust!
Use at your own risk.
I take NO responsibility for this advice.
I reject your reality and substitute my own.