I use a 10:1 water to (liquid) molasses mix, no heater - generally hot where i live, takes a while, helps if you give it a scrub and agitate it every few days

+1 on the steam clean first

Lol at the smell - my vat has been banished to the far end of our yard

I am in no way an engineer of any sort, but as far as i know electrolysis will eat the weakest metals first, so if its an ally dizzy, go the molasses