Old Trap

[MCH2]

A soak in vinegar will take the rust off nicely.  Check every few hours.

[kac]

Straight vinegar or diluted? I usually use reverse electrolysis but need a better rectifier 3-6 amps to get this crust off.

[Rick N. MI]

Use white vinegar. I have had to let soak for a week to get a lot of rust off.

Electrolysis is faster.

[kac]

Thanks