I used to manage a housekeeping department in a hotel for several years. Ozone machines are great and we have had to use it to clear out some very serious funk on many occasions. I actually preferred using those as much as possible over chemical treatments (odor counteractants) I will offer my advice based on my experience with Ozone. If you have the extra money, get one designed to cover square footage way beyond the area you intend to use it on(especially helpful if you want to clear it quickly) They offer some small ozone machines that plug into an outlet like a glade plug in. Those work very slowly and are really only intended for small areas like a bathroom, I do not recommend them, I have tested them, in a small office, it barely did anything. Some of the ozone machine models come with a timer and a dial to adjust the amount of ozone generated. Never be in the same room will it's operating (unless to turn on or off), the machine creates O3, you can actually suffocate if you spend a lot of time in the same room. Always ventilate the area well before going back into the room (as simple as opening a window or door with a fan going for a few minutes). Always handle your ozone machine with care, the technology uses ceramic plates to generate the Ozone and are fragile, break those and you break your machine. Hopefully a replacement ceramic plate is available, if not, you're getting a new machine. As far as maintenance, the ceramic plates do need to be cleaned occasionally, you will know when your machine just doesn't seem to be very effective. Refer to the manufacturers instructions on cleaning and maintenance.
I own a couple of small air purifiers for my place (for my allergies, and they help a lot) They do produce some ozone (slightly below the legal limit to be occupying a room while running). If I smoke in the same room with them running, an hour or two goes by and the smell is gone (even with blunts) Don't think they can keep up with scrubbing some stanky danky air though.
