Re: Mold around tub
Caulking isn't terribly difficult, however it does take some finesse and technique to apply it cleanly.
You will need to remove the old caulk first, as the mold is imbedded and behind it. Once the caulk is removed, the area needs to be thoroughly cleaned, then treated with a bleach solution to kill any remaining mildew and remove stains.
I personally do not like silicone caulks, as they are messy to apply and fail about as quickly as any other type of caulk. Latex caulks are the easiest to work with because they're water clean-up. Choose a tub and tile caulk.
It is easiest to use the type of tubes that require a caulking gun to apply. The smaller squeeze tubes are much harder to squeeze by hand to apply an even bead. Start by cutting the tip off the tube at 45* to reveal a hole 1/8". Have a wet rag handy and squeeze the trigger until caulking starts to exit the tube, wipe it clean.
Start in the corner, squeezing the trigger as you draw the caulk along the joint. Use the tip of the tube to lightly press the caulk into the joint as you go. Once the caulk is laid, wet your finger really well on the rag, then draw it along the caulk in 2 - 3" strokes, wiping off your finger between strokes. This will press the caulk into place and finish off the surface. Once you've made one pass with the short strokes, go back with a fresh wet finger and draw it along the entire length of the joint to have a perfectly smooth joint all the way along.
This is where the beauty of latex caulk comes in. If at first you don't succeed, simply wipe the caulking out and start over. Be sure to rinse your rag often. Take your time and be patient.
Lastly, if you've got mold and wall damage as seriously as you describe, you're going to either get the landlord to remediate it or move, as it is unhealthy to live with a problem like this.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!