As others have stated, ozone works well, and you can buy an ozone generator for cheap on Amazon. You absolutely don't want to be in the room when the ozone generator is running or for a few hours afterwards. Many have timers so you can set them and not reenter the room for the timer period plus a few hours longer for the ozone to decompose back to oxygen. Otherwise, run the ozonator on an extension cord from outside, and unplug it, wait a couple of hours then open the doors and windows.
One other thing to be aware of, the ozone oxidizes organic molecules, which includes plastics, particularly soft plastics and elastomers. If you use too much ozone you can end up destroying rubber, elastics and even synthetic fabrics.
