I use Evaporust on most of my stuff. You could look for agricultural vinegar 20% strength instead of the lesser 10-12% that household vinegar is.
I've use plastic bags to hold stuff like rods. You could do the same on the larger things to reduce the volume needed. I also made a vessel out of 1-1/2" pvc pipe with a cap and a drain valve on the end for things like control rods.
At some point, for things like frames, cabs, etc. it''s just cheaper to get them blasted. Evaporust does make a gel product, but it's more expensive than their liquid stuff. I tried it without a lot of success. The first tiny jug I got was too thick and they sent me a replacement. It has to stay wet to work.
My son-in-law has a garbage can set up for electrolysis that he dunks stuff in. Works with a battery charger. He uses washing soda and water for the electrolyte and rebar for cathodes (or anodes

). He's done stuff like driveshafts and a bell housing in it.