How do I clean my bathroom tub?

Try a good degreaser like TSP.

Hydrogen peroxide in a spray bottle to kill the bacteria and yucky stuff. Then rinse with water after the fizzing stops. To make it shine again, use bar keeper's friend and scotch brite pads. It will make it gleam as if it were new and eliminate the water stains. Here is a kit of both the pads and bar keeper's friend that I've used in the past with success: https://amzn.to/2Q3Ug7R

I suggest spraying it with vinegar and let it sit on it, then sprinkle on baking soda and moisten. Let it set awhile and then use sponge to wipe it off.

This sounds too easy, but get yourself a few Mr. Clean Magic Sponges. Rinse and repeat. Did a miracle that neither beach or Comet did in my tub.

I suspect you only need to clean it with whatever products you would normally use to clean the tub. However, it might require a lot more good old fashioned elbow grease!

Comet Cleanser and a Fine Steel Wool, not SOS Pads, and likely some sort of irritant like: White Vinegar. And Be very Gentle with the Steel Wool, as that tub is likely porcelain or fiberglas.

works or oven cleaner

Been there, done that. After a few hours of scrubbing with Comet and a no-scratch kitchen sponge I was almost convinced the grime had eaten into the porcelain. The bottom of the tub was the worst. There was those sticky no-slip flower shaped stickers on the bottom that I had to carefully remove with a razor blade. After hours of scrubbing the sides were coming clean, but the bottom was still grungy so I traded out to a sponge with the scratchy side to finish the bottom. When I got 99% off the bottom I switched to Soft Scrub and a no-scratch sponge, and the bathtub looked great. This was a rental, and the landlord had previewed and told us to do whatever we wanted to do to make it liveable to our standards. When he came to inspect after all the work was done, he took one look at the bathroom and said "Did you put in a new bathtub?". Made it all worthwhile.

Heat up 1 cup of white vinegar, mix in about 1/4 cup of Dawn Premium. Not the dollar store kind, because it is too thin. When mixed, pour into a spray bottle and fill with water. Shake. Spray down the grout and let it sit overnight. In the morning rinse. If you have stubborn stains, spray again. Use this mixture a few times a week. It will keep your grout and tiles clean. Also works wonders in the toilet bowl to keep hard water stains at bay. Oh you only have to heat the vinegar one time when you add the Dawn.

Get in your hands and knees and scrub.

Gathering it's soap scum and everyday grunge, yes, generic Comet should work fine.

If you've rust, then even after using Lyme Away or CLR, the source of the rust may still be there.

Let us know what you're trying to clean, if you know.

Here is how I clean mine https://chascrazycreations.com/clean-bathroom-natural-products/