Green’s Dictionary of Slang

maun n.

(UK Und.) a hand; thus phr. tip us your mauns, give me your hands, shake hands.

[UK]G. Kent Modern Flash Dict. 22: Mauns, tip us your – give me your hand.
[UK]Flash Dict. in Sinks of London Laid Open [as cit. 1835].
[UK]Duncombe New and Improved Flash Dict. n.p.: Mauns, to tip tip us your mauns; shake hands, or give me your hand.