Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to refinish bathtubs [title] Clean the entire surface of the bathtub with chemical cleaners to remove any soap scum and dirt residue. [step] The chemical cleaners will also help the bonding agent adhere to the surface. [title] Rinse and dry all surfaces thoroughly.

Ending1: [title] Use a palm sander to gently roughen the surfaces you plan to refinish to make it easier for the paint to bond with the surface. [title] Tape paper or plastic over any surfaces you do not want to paint. Ending2: [title] Remove tub counter tops with an acrylic acid based cleaner with a small brush or the brush or spatula. [title] Remove mold, insects, and wax from the tub. Ending3: [step] Run a vapor bath if needed to remove soap scum or dirt residue from the bathtub. [title] Detach the tub frame by jacking the top part of it upwards and slamming it against the side and wall. Ending4: [title] Identify and avoid leaking faucets or shower heads, such as those with a drain. [title] Remove the line attaching a shower drain to the faucet.

Answer format: ending1/ending2/ending3/ending4