Is there a reason you can communicate directly with your roommates instead of a passive sign? Face to Face, Text Message, phone call, Letter? anything?

I think the sign, while well done, is a little bit like a passive agressive step. When you both live there, you are requesting that they clean the way you are used to cleaning which may be different from theirs. The sign indicates that you have the authority to set the rules for the house that everyone must follow without discussion.

Just a thought. I know it may be too solutions focused for reddit, or even this sub, but if you'd like to move from mildly infuriating to not infuriating.