It does the job!
Expel works! I discovered this product when I worked in the nursing home business over 20 years ago.  I've been using it ever since.  I use it daily in my cat box at home and to eliminate any random odors from cooking, dirt tracked into the house or other sources.  It looks like water and has no smell of its own.  It does not mask bad odors, it just makes them go away.  It takes very little to be effective, just a light squirt from the spray bottle.  A gallon lasts me a year or longer.  I have never seen it discolor fabric or leave a mark on a hard surface, including wood floors.  I was very glad to see it on Amazon.  It's not available locally where I live and ordering directly from the manufacturer was a hassle.
Rating: 5 stars