On my B-12 soak, avoided big smoke by separating the wash.
Drained used oil into new clean container, then collected whatever B-12 wash mixture separately in an older container. After soaking done and confirming cylinders dry, refill used oil, added a small amount of MMO to re-lube the rings. The startup smoke minimal as if mainly MMO burning off.
Sharing pics of the drip brew evaporated about a day
View attachment 233892
View attachment 233893