I have a friend who lets a couple properties. He just evicted a particularly obnoxious tenant who was very nasty and aggressive. He is concerned that she may have been using P.

He wants to sell the property and he needs to ensure that if P was smoked there, any residue is below the legal contamination threshold. He is wondering if he had the carpet commercially cleaned, would that be sufficient to make a significant difference to any test? He is certain P was not cooked on the premises but is having trouble finding this kind of information and I am wondering if anyone here would know. He wants to do as much as he can to fix any problems before official testing is carried out.