Originally Posted by BCRider

Mineral spirits or Varsol. Both are much cheaper than even bulk WD40. And you can pour the solvent into a jar, let it settle and then decant the clear solvent back out and keep using it many times over.

Best of all it is not corrosive like Simple Green or other citrus based degreasers. Such strong detergents are OK if only exposed to the parts for a while but with longer term soakings they have been reported to produce corrosion on chains and etch into anodized or raw aluminium parts. Something that solvent doesn't do.

Environmental concerns? SG or citrus degreasers are only useable for a one shot or at most two shot sort of deal. Meanwhile I can reuse my mineral spirits many multiple times by just letting the grit and gunk settle out so it is transparent again. Sure it picks up a brownish tea like coloring but that's just the oil and grease which are fine. The harmful grit settles to the bottom. And when it's finally too far gone I pour it into the waste motor oil to be sent in for re-refining. So it's likely better for the environment in the long run than the powerful detergents which carry the waste grease and oil into the sewer system.