One last sign...

I posted a few days ago about translating a sign "Please keep [this] [door-type-thing] closed" into all the languages my students and I speak/are learning. But I forgot to ask about Portuguese! Shame on me. Can anybody help me out? Here's what I have thus far in other languages:

Keep closed, please!
请随手关门！
Geschlossen halten bitte! Bitte geschlossen halten!
これを閉まって下さい これを閉めて下さい！
Veuillez fermer la porte!
Пожалуйста, держите крышку закрытой! Пожалуйста, держите закрытым!
¡Cierre esto, por favor! This went from "a little odd" to "does not work" so I'll change it to ¡Cierre la puerta, por favor! but please realize I a) do no speak Spanish b) can not tell who is a native speaker from a 1-2 sentence post and c) would really rather not use the word door, despite resigning myself to using it in French (which I also do not speak)
Coinnigh seo dúnta, le do thoil!
Mantenha a porta fechada por favor! (should there be a comma here, or a ¡ used?)


Thank you all so much, my students love the sign!

EDIT: Thanks for the help with the others, signs are weird things. If you know the Portuguese, please let me know!

And watch out, this has been such a hit I may be at you to help me make another sign for "No food or drink in the lab, please", but not right at this moment. :)

EDIT 2: More changes made. Thanks for the Portuguese!!