If you want to get metal really clean for welding then you have to get rid of oxidation (grinding) and grease (degreasing cleaner). Acetone would probably work, but it is a pretty "polar" solvent (un-greasy). Something like paint thinner will get rid of greasy stuff better.
Do be careful of fire, though!
Chris
It depends on what you are wanting to do but muratic acid will work very well (It etches the metal), you can get it at a hardware store (Lowes, Home Depot, Ace). Make shure that you wear all the personal protective equipment required.
Acetone is a highly volitile (one of the ffastes evaporating I believe), flammable solvnt and presents a variety of shop hazards but leaves no residue (except any residual from the dirt you were trying to remove to begin with) and, with some caution I use it myself... as well as other paint-thinner solvents (eg MEK) which evaporate a bit slower and can penetrate into various films more effectively, so they effectively do clean better. Ever since an episode of unintentional production of highly toxic Phosgene gas, Ive been very wary and carefull to be sure ALL residues are absent from any metal I'm welding, and suggest you err on the side of caution yourself...
I have found Bar Keepers Friend, a very slightly abrasive polishing cleanser fortified with a dilute, corrosion removing acid, to be the most effective, safest, and economical cleaner I've run accross... I use the acetone- or if i'm in a jam at an odd hour I'll use rubbing alchol- as a rinse agent to dry off the water before any flash of rust can form.
Note that any solvent I've found will do nothing to remove oxides and serves only as a pre-cleaner before whatever kind of abrasive prep for processes where cleanliness is critical (like a brazed joint) but this powdered cleanser usually does it in one step.
Regarding the suggestion to use Fantastic, it's a fair cleaner. There are stronger cleaners available at paint stores, though.
You may also consider trying a regular automatic diswasher detergent- Ive been advised to use any brand except Cascade- (and not dish detergent) as an experiment. It often does surprisingly well, and you might have some in your kitchen at this moment.
Regards,
d