既然他们会自己漆，让他们自己复原，

说好不重新漆两个房间收五百，You need to download a damage addendum, such as this one: http://www.rentgrandin.com/pdf/Damage%20Addendum.pdf

and in second page, put down, tenant agrees to paint room 1 and room 2 in white upon moving out.  Otherwise $500 shall be deducted from the security deposit. 

去找两个amigo两百五一天还做不完？