At prime area?

Can charge non-customers. RM1 per entry.

Is your cafe, order and pay first, then serve the food? If yes, then assign a junior staff to look after the toilets. Ask for receipt, to allow to use toilet.

A bit troublesome. Customers may complain. Maybe you put up a notice there, nicely written. Ppl will understand.

Make sure the toilets are clean and dry all the time. Ppl don't mind paying.

Some mcd in Europe do that, if their outlets are small. Big ones ok, can pretend to be customers then go toilet first. Haha.