What can I use to remove caulk from around the bathtub? Also, what is the correct product to use when I caulk the tub again? Obviously, I need something waterproof, but ideally I'd like the caulk not to be plainly visible.
Removing caulk isn't difficult, only time-consuming. The name of the game is perseverance, particularly if you are dealing with several layers that were applied in succession over time. Given the nature of the task, it's important to arm yourself with the right tools, starting with a utility knife and a razor scraper, both fitted with new blades. If you'll be tackling a wall-to-tub joint, opt for a church key can opener or a pointed scraper; either can be handy if you need to go digging for any stubborn remnants. Then again, you might get lucky-sometimes after loosening one end, a strand of caulk pulls away easily. Much depends on the age and quality of the installation.
To begin, hold the utility knife so that it's more or less perpendicular to the joint, then run the blade along the caulk joint. If the caulking proves too hard to slice, try softening it with a heat gun (do this carefully). Now remove whatever caulk you are able to cut free. Follow with a razor scraper. Wielded at a shallow angle in relation to the surface, the razor should remove any caulk bits still stuck to the tiles or tub. If you find evidence of mildew, thoroughly scrub the area with full-strength vinegar.
Compared with the hassle of removing caulk, replacing it is a cakewalk; even a complete novice can apply a fresh bead of caulk to a bathtub. Just remember to use a caulking product specially formulated for use in kitchens and baths (packages are clearly marked). Caulk comes in many colors, but if you don't want to see it, choose a clear variety. Before you begin, steady the nozzle of the caulking tube about 1/8 inch away from the surface and at a 30-degree angle.
As you work, try to force any excess caulk into the joint; failing that, wipe the caulk onto a towel you've kept at the ready. Clean any caulk you misapply before it has the chance to harden. Finally, slide your wetted finger along the joint once more. Doing so eliminates any imperfections in the bead, ensuring a smooth finish.