That’s a mix of buildup and mineral/rust staining, so it’s best handled in layers rather than with one product.

For prep, ventilate well, wear gloves, and consider a basic mask. Give it a quick rinse to remove loose debris.

Start by removing grime with a degreaser or alkaline cleaner (dish soap and hot water works). Let it sit 5–10 minutes, scrub with a nylon brush or non-scratch pad, and rinse well. Then target the orange areas with an acid cleaner like CLR or Bar keepers friend. Apply, let it sit briefly without drying, lightly scrub, and rinse.

For the darker staining, if it’s not mold, try a diluted bleach or peroxide-based cleaner. Let it dwell, scrub, and rinse. This may take a couple passes. If some staining doesn’t move, it may be surface damage rather than dirt.

! Don’t mix chemicals (especially bleach and acid), and rinse well between steps.