We have several rentals. One bathtub had been cleaned by someone with LYE, the finish was gone, it looked horrible. I just had it resurfaced by Surface Tech in Salt Lake City, there are several companies who do it. It is guaranteed for 7 years and looks beautiful. It is surely a lot less work and trouble than changing tubs. Another alternative is the company that re-lines the tub with a new plastic mold - it runs about $1000 dollars but is a beautiful job.