Bleach
Watered down bleach in an old spray bottle. It's dirt cheap, and keeps the mould off the grout.
( Invisible Wizard - 10th Level Nerf-herder, Sun 22 Dec 2024, 8:36, archived)

I heard doing that encourages mould.

( brb Learn Ukrainian and prepare for a referendum, Sun 22 Dec 2024, 15:00, archived)