You could even use WD40 on some Patches, any kind of Oil. just some thing to Lubricate the bore while you brush it, then lightly Oil and Dry Patch and Im sure that'll get you by untill you get Home.
Now I dont know who Insist that you need (Boiling Water) I've never used Boiling Water....Hot Water is fine and so is just plain Ol Water with some Soap, Im sure you could get by without the Soap even if you had to. Heck you could just Spit on the Brush and clean it. Im sure the Brass Brush does most of the cleaning anyway.
If Im wrong Please quote....and I just use Pyro RS so dont hurt me too bad if you have to use a different Powder and need a different way to do it.
(BP)