Hi Biggerpockets Community, it's my first post ... I read other post just before I wrote this, so I have some insights into this matter. But I could still use some advice.

Our renter complained that she smelt something Friday. She happen to be leaving that same day for the weekend and we agreed I'd check it out.  I confirmed that the smell is likely a dead rodent. My husband inspected the attic and he didn't find the source but the smell was the strongest in the attic. We used Bac A Zap in the attic. After a few hours it still smells but it was much better. We apologize and issued a credit of $200. for the month. 

This morning she sends a text saying the smell is much worse, in her hair and clothes. She later text saying she is going to find a hotel with a washer/dryer so she can wash clothes because she doesn't want to bring the smell with her to work tomorrow.  I agreed it's a good idea to respray but from what I read it will take anywhere from 5 days to 3 weeks for the smell to go away and I can't justify paying for a hotel for that time. I did however offer her out on her lease with the full deposit back in advance if she can find alternate housing.

We share a wall and part of the attic and I also smell dead animal. After about a few minutes with the windows and a candle it fades into the background. 

 We have no complaints about her, "felt bad" and that's why we decided to give her a credit to acknowledge it sucks to smell decaying rats in your house, we get it. However,  I could use actual language you've used to deescalate complaints that can't easily be resolved. I let her know I'll spray the Bac A Zap in the attic again and do another search for a rodent (which I don't think I'll find), but the stench might not go away for a while. 

Amateur take away: 

1. DON'T use poison! Our be prepared for the stench of rotting animal.  I'm certain my sense of smell isn't the best but I find it easily masked with a candle but your tenant won't. Some will bug you about it repeatedly, I've gotten 5 lengthy text in the last 3 days.

2. When you first hear a rodent or get a complaint about a rodent, call a exterminator! If your handy you can do it yourself but if your squeamish about rodents your going to do a half-*** job and the population can QUICKLY explode. It sounded like rats where building a small empire in our attic. It turns out we let a tree overgrow against the house and they found tiny little access points that hadn't been sealed to get into the attic. We've lived here 17 years and have had the occasional rat in the crawl space but nothing like this. We tried to handle it ourselves and here we are!

3. Update lease to specifically address rodent problems. I have a arbitration clause and illegality clause (both of which I had to add to lease) but no rodent clause. If anyone has such a clause please share it. 

Feel free to add other take away, I'm all ears. Looking for specific suggestions on kindly but firmly deescalating the situation. While acknowledging I can't make the smell go away.