Canvas bag gone mouldy

[MojoMoon]

I have a thick canvas bag that I use a lot on my bike and the inside is going a bit mouldy and smells musty.

Probably because it regularly has a damp towel in it post swim/gym (or it did when those were open)

What can I go to clean it up and freshen it up?
Thanks!

Wash it?

put it in the washing machine.
my swimming/beach bag gets goes in the washer a couple of tmes a year.

Sorry I should have been clearer - it's a bike pannier style bag (with plastic frame and metal fittings). It won't go on a washing machine without damaging either it or the machine

What colour is it?
I'd rinse it with a weak bleach solution, leave 10 mins, scrub and rinse as best you can, and then leave it to dry properly- like ontop of the radiator.

Or maybe scrub with vanish coloursafe or similar?

When the sun is strong, can you leave it in bright sunlight once a week?

Brush off any mould that will brush away then spray on a solution of 1 part vinegar, 1 part bicarb and 2 parts water. Scrub it in and wipe with over with a damp cloth.

(Worked on a mouldy fabric pushchair seat)

Lemon juice and bicarb might work too.