[alsalp]

Muratic acis from Lowes. Nasty but quick. Can dilute it but will take longer. I do about a 1:1 with water and let it sit for an afternoon or overnight . Depends on strength. After I'm satisfied with rust removal I rinse really well in a baking soda solution. rinse with water. Then after it drys and flash rusts (yellow) i treat with OSPHO phosporic acid. This etches and protects metal. Wipe dry. Scuff any powdery residue and paint

[north]

be really careful in confined spaces with phosphoric acid, vapors are very prone to flash. All it takes is a light switch or static electricity to set off a blast

[alsalp]

I guess it's not obvious that one should work with acids in an open area

[dataway]

I have used a lot muratic acid to clean parts before plating ... would typically hang the part from a copper wire into the acid .... I noticed everything within about three feet of the open container was starting to rust. So better to cover it or use it in a well ventilated area. Undiluted muratic acid makes quick work of rust, but of course is impractical for large items unless you are working outside and want to store gallons of the stuff.

I only use it now to remove zinc plating before replating, or on nuts and bolts, too harsh for delicate parts.