I find the "dryer" alcohol cuts thru the flux from rosin core solder quite well. Lesses %s need multiple passes to clean.
My local electronics supplier has it in gallon bottles. I picked one up at some point, we put a few ounces at a time in a small pump jar (not sure what the actual name is, same square bottle with spring top, push down a couple times and top fills with some alcohol for the cleaning brush - same thing our shop at work uses for cleaning up reworked boards).
http://www.mouser.com/ProductDetail/Menda/35309/?qs=%2fha2pyFadugResYH%252b75ZqvYV6knOqbetNdKoUVscgdY%3d
which my supplier also had, along with a hog hair bursh
http://www.mouser.com/ProductDetail/MG-Chemicals/857/?qs=sGAEpiMZZMvJqaFk9BIiv6jhjM0Pk6JzPq2RhIeIS6c%3d
This one works well as the bristles are longer and the pins of shields can go thru the bristles.
Hopefully the forum/IE11 won't stick extra http stuff at the front of the links ...