My kitchen sink is called the "Po-Boy Sink"
I had an old 5 gallon collapsible water jug that had a tear around the spigot end.

I cut the spigot end off leaving the handle on.
Poked 2 more holes and used 2 of those plastic grommets and some 1/4 rope to make another handle.

Fold flat, doesn't stay wet, and slips into pack on edge.
Soap/squeegee go in a small mesh bag in food pack side pouch.