There's a mixture out on the 'net called Ed's Red. It's a soup of;
1/3 acetone (or lacquer thinner which is mostly acetone),
1/3 mineral spirits (Varsol cleaning solvent or low odor paint thinner for oil house paint)
1/3 red automatic transimission fluid.
I made some up a while back and it does a fantastic job of cutting through powder residue and will also melt through packing oils and greases like a hot knife through butter. And best of all thanks to the ATF content it'll leave a light protective oil film in its wake. I'll be making up a tub of it for my eventual (hopefully) arrival of my own two "grease spots". Oh, and avoid using this mix on wood, rubber or plastics. It'll be hard on the finish or in the case of rubber and plastics may well melt them.
Use the Ed's Red outdoors or in well ventilated areas or only in very small quantities dabbed on a rag or cleaning patch. It's not only very flammable but it stinks to high hell of solvent. It may mean shooting and good times to us gun nutz but it won't find favour with the other half... nor, for that matter, do you want to live in the house after using a lot of it.