Do you offer towels to your guest? I make it available but they really don't take care of it. My last guest left the towel full of make up. It was so bad, I threw it out. I did no even bother.
What do you all do?
[Title updated by Community Manager for relevancy]
You could place a pack of makeup remover pads maybe they'll get the hint if they can use something besides your towels. Makeup on towel should wash out very well so just try laundering it first before you throw it out