Ouch, I hope it doesn't mushroom into something worse!

Let him keep the old ones and just buy a new pair. Problem solved!

Boil them in hot water, then empty the pot onto your dad. Or, you could try telling him. That might work better!

He sounds like a real fungi. His attitude doesn't leave you mushroom to manoeuvre. It's a real shiitake situation.

Pee on them in the shower and then he will never wear them again.

Have a talk with your dad or if that doesn't work just keep them hidden from him.

I hope you can avoid that

Who wears flip-flops in the shower?

Sharing is caring.

I'd say to get a separate pair. Just make it a different color, or find some way to distinguish! I don't think you'd get his foot fungus unless it's a constantly repeated experience. though, so hopefully that alleviates any worry.