For...a 'while' now, we have had a loose floor tile in the bathroom. A couple of weeks ago, I tried taking the easy way out, and just chipping out and replacing the grout around that tile...and that helped for a week or so. Finally, my wife was able to convince me to do the 'right thing', and just pull the tile up, and start from scratch.
Of course, things are not ever that easy. First, roughly half the mastic stuck to the floor, and half stuck to the back of the tile. And, there was a suspicious looking intermittent black staining on the subfloor, which is actually two problems in one: it's most likely some mildew/mold(not 100% unexpected having a loose tile on the damp bathroom floor), and, from everything I have read...I shouldn't be able to see the wooden subfloor. The current standard for doing floors in bathrooms(and I only know this because I studied to fix this tile), is laying cement board over the wood subfloor.
I am lacking a cement board layer. Bummer.
I'm not in a position to address this problem right now, either skill wise, or finance wise. Problem noted, and added to the wish list somewhere in between a camping trailer/boat/or an outfitted elk hunt.
Cleaning the floor wasn't tough, and it didn't take too long, as long as you don't count the drying times. Cleaning the old mastic off was the only real sweaty part...and getting it off the floor was 18 times easier than getting it off the back of the tile I had to reuse. As I was using a putty knife and hammer to remove the old stuff from the back of the tile, I was constantly worried I was going to hit too hard, or at the wrong angle and break the tile.
Once the mastic was off the floor, I gave it two doses of bleach, letting it dry overnight. Then I painted on a latex based sealant to protect the wooden subfloor until we decided to redo the whole bathroom, letting it dry most of the day yesterday before I finally laid some knew mastic, and set the old tile back in. It's currently setting in the bathroom with a 5-gallon bucket full of something on it, weighing it down. I'll let it set a good 36-48 hours before grouting it.
The only real negative with the process(other than learning I will need fix the whole floor at some point(or sell the house!) is that it takes the upstairs bathroom mostly out of business for a several day period, meaning no soaking bubble baths for me while the wife and kids are out of the house...just the downstairs shower stall.