Before you start, something you need to realize is that this is going to be a long, laborious process. DO NOT embark on this process unless you are actually prepared to see it all the way through. The whole process, including proper drying time, is going to take at least three days to do so do not start on this task unless you have those three days to spare. You will be able to bathe during most of that time, but right at the end you will not be able to use your shower while the new caulk is drying.

Once you have resolved to see this all the way through, take your caulk-away tool and then start at one end of your bathtub. Starting at that end, push the caulk-away tool through the old caulk, bringing as much of it up as possible. While the tool will do a very good job of removing the old caulk layer, you should see immediately that there are going to be very fine areas in which it comes up short. At the end of the caulk-away segment of use, you will still have some residue and fibers of old caulk left on the joint between your bathtub and the wall.

Clean up the residue with the razor, before using a hand held vacuum device to remove everything else from the joint. With that done, apply rubbing alcohol to the whole joint area to remove anything that is left, before leaving the joint to dry. You need to make absolutely sure that the joint is completely dry before you proceed to the next step. If the old caulk has been failing for a very long time, you might find the joint to be extremely wet. If this is the case, you can use something like an oscillating fan to speed up the drying process, although it may take a few days to do on top of the three day minimum that was earlier stipulated at the start of this section.