About two years ago, I had the bathtub refinished. After it was done, I caulked all around the tub. After 2 years, the caulking got moldy so I removed it and recaulked with a different make of caulking. It didn't hold at all and I removed the new caulking. I let the tub dry out for two weeks before putting in the new caulking. The new caulking is already peeling and I did clean the areas with alcohol. Would it make sense to grout the entire area and then apply caulking over it? Will rubbing alcohol actually remove old caulking? Does the brand of caulking make any difference? The tiles along the tub have little bumps on them which make it almost impossible to remove all of the old silicon. I am almost at my wits end and am considering leaving up the plastic drop cloths no matter what my wife says.
Alcohol won't remove much residue of silicone from a tub. As a refinisher, I have found the best way to remove caulk is to cut it out and pull it. I also use acetone to remove alot of the residue. It's hard work, but it helps the process. Mildew on caulk also comes from poor ventalation in the bathroom. You may want to think about installing a bathroom vent fan if you already haven't. The best caulk I have found that I use often is PolySeamSeal. It comes in a white tube with blue lettering. It looks like a frosting bag (like you would decorate a cake with). It applies very quickly and it's a snap to clean up.
Just to echo the Poly seam seal remark as being the best I have found, and to mention a dry sponge and elbow grease with a razor scrapper back (gently) is the best chaulk removal system. (Along with the pull and fingernail scratch method)..
Of course homeowner verses a production employee will vary...":^)