So, I worked in a hostel as the assistant manager and my little service dog lived there with me. When I got there the place was overrun with fleas. My dog did not have fleas so they were probably brought in by the assistant manager before me.
It wasn't like I could kick everyone out of the hostel for a few days while I bug bombed and cleaned everything so I started looking for a nontoxic solution. I tried baking powder mixed with rosemary and a few other natural remedies. None of those helped. Finally I went to Home Depot and found this super cheap nontoxic insect spray. http://www.homedepot.com/p/EcoSmart-64-oz-Ready-to-Use-Organic-Home-Pest... It worked and it smells good. It was cool. Of course, some people still complained about it but that is to be expected. Someone always complains.
I found it on amazon but it was kind of expensive for the big bottle. There are other similar brands thas I am sure work well too.