What would you write in this case? (a sign in a fitting room)

Once in a fitting room of one clothes store in Taiwan I saw a sign saying something like

Watch your lipstick carefully no to touch the clothes you are trying on.

While the main concern was pretty much clear to me—the owner of the store didn't want to have lipstick stains on the clothes he was selling—I kind of suspected that the way the thought was expressed was wrong. I tried to come up with my own better version and failed. So, if you were the owner of that store, what would you write on that sign?

Solution 1:

The given sentence can be made grammatically correct with very little modification:

Watch your lipstick carefully so it does not touch the clothes you are trying on.

However, I recommend the following as less awkward. Phrases in brackets are optional, with vertical bars separating equivalent options. The fewer words, the more brusque it sounds. Somewhere in there is a balance between politeness and conciseness.

[Please] [be careful to|carefully] keep [your] lipstick off [the|our] clothes [you are trying on]

I personally like:

Please be careful to keep lipstick off the clothes. Thank you!

Solution 2:

Please be careful not to get lipstick on the clothes.

Or perhaps,

Please be careful not to let the clothes touch your lipstick.

Solution 3:

I would use a short

Avoid staining clothes with lipstick.

Solution 4:

While changing do not stain clothes with lipstick.