Paper towels! Barring that, napkins.
If I don't have ANYTHING like that I would resort to a throwaway piece of paper haha.
Well sometimes i use my shirt (just now i snezzed irony lol)
I usually use my shirt if it's minor.
If it's major I'll try to wipe it off or look for a papery substance thing.
i'm gross
I blow my nose into my fingers (unsanitary, I know), then wipe it off on anything soft I find.