knob hands

(British English)

A man's hands made unclean due to neglecting to perform the necessary ablutions after using the bathroom.

Oi, all the taps are broken! That means that bloke coming out of the gents' has knob hands.

knob hand door touch

The process in which you open the door to the toilet after using it without washing your hands!

Wow, did you see that bloke? He just did a knob hand door touch! Be careful