Bathtub is still dirty

I got cleaning supplies today. Tried scrubbing my bathtub. I got stuff you spray on it, didn’t know you were supposed to wait “several” minutes before scrubbing. Sprayed it again and waited two minutes, and it got some of the dirt off. Sprayed it again and waited almost an hour, still didn’t get everything off.

I’ll keep it dirty. Maybe I should use the mop.