To make polite, should I write...?

[Wchanit]

I am going to make a card to remind friends about their schedule for cleaning lab room.

I don't want to say like "don't forget to clean", this week is your turn for cleaning".

To make polite, should I write...?

Just reminder that this week of a cleaning schedule is already made.
Thanks
(Teacher's sign here).

please share your ideas and I will pick one of them.
TKs

[Haihao]

Our lab is asking her caretaker of this week to clean her up in time!

[Beeesneees]

This week's lab room cleaning schedule has now been produced (or possibly, 'is now posted on the notice board' or similar). Please would all students check their place on the rota. If there are any issues, please report them to ... in time for adjustments to be made.
Thanks.
...
_________________
Cheers m' dears!

[Wchanit]

The schedule is already posed on the board. I just want to make a short notice to a person who is responsible in some week. This note will be put on his or her table when he or she forgets to clean up in time.

[Beeesneees]

Thanks for the clarification.

How about:
"Just a reminder that you have a task on this week's cleaning rota. Thanks ... "
"This is a quick reminder that you have..."
"This is a short note to remind you that you have..."
"Have you remembered that you have..."
"Please remember that you have..."
_________________
Cheers m' dears!