How to get rid of the black from around my shower and glass?

Straight bleach and a stiff brush. If that doesn't take it off completely, rinse it off really well and use clr (calcium, lime, and rust) let it sit for a bit then scrub with a stiff brush

spray with straight bleach, scrub with brush. Keep air moving in the bathroom because moisture causes mold to grow.

If you are referring to mold or dirt, there is a product "wet and forget shower". I used it twice a week for a couple of weeks and now once a week to keep clean. It's a no scrub solution. If you want to try and clean it another way, take papertowels and spritz with a bleach solution (50/50 with water) until they will "stick". Line the area with the papertowels and leave for a couple of hours. It will bleach out the area without scrubbing.

Bleach is a good option to get rid of mold, but make sure you do not use it in a confined space. You need good ventilation because chlorine fumes can be very harmful to you. Just be careful and don't spend a long period of time scrubbing.