I've used black powder (it is also corrosive if left uncleaned) solvents and they work. Use them like you would Hoppes#9 and the lube up the rifle after cleaning.
I've used hot water. Dried off what was left of the water with a hair dryer, or by setting the parts in the hot sunlight on the deck rail (yeah, clean my guns out on the deck sometimes) and then lubing them up after they dry.
Hot water works really well. The hotter it is the quicker it dries out.
When using hot water, make sure you get it all flushed out good. As stated, the water dissolves and flushes away the salt/compounds left on the metal that absorb moisture from the air and rust/corrode your gun - so make sure you get them out. Not that big a deal if you can use a dish rinser/sprayer in the kitchen sink, or dunk the parts under water in the tub or a big sink.
If I use the water method, I use a spray oil to insure I get oil back in all the cracks/crevices of the lower and the upper/front sight base, flash suppressor, etc. No use removing all the powder residue and lube only to have it start rusting somewhere you didn't get lube/rust preventive back on before you re-assembled the rifle.