How much to take out of security deposit for drugs + damages

[Derek Snyder]

Hello all,

This past week, I had a renter move out who has been great until now. After he moved out, we noticed a few things wrong. First, the whole apartment smelled like pot (illegal in Indiana), then we found some of it in two of the rooms, dog pee stains on the carpet, multiple pieces of furniture left in the rooms, trash everywhere, animals in the freezer, full fridge, mold in the bathroom, chewed up internet cords, and holes in the carpet. 

They paid a $500 deposit, $200 non-refundable pet deposit to clean carpets, and a $300 pet deposit. Then, I told them I would buy one of their A/C units for $50. 

Oh yea, and they didn't give me a 30 day written notice before vacating the residence (as stated in the lease).

So right now, I owe them $850 minus damages.  It took my wife and I 5 hours to clean the residence and then we had to move all their stuff out. 

What is a fair amount to give back to them?

Thank you all for your advice. 

Derek