The floor pan is such a large area i had to tackle it in three sections.
Rust removal floor pan.
The front where the pedals are the middle under and behind the front seats then the section under the rear seats.
Take a sponge with a scrubber and scrub at all of the rust spots using the heavy duty scrubbing side.
If you replace left and right side partial panels and leave the original tunnel intact you re welding about ten more feet of sheet metal versus replacing the whole floor.
Then make sure you properly seal the floor pans.
To remove the old grease and waxoyl i have used bits of the old carpet and cut into rectangles sort of five by seven inches or so.
Curiously replacing the full floor pan is actually less work than doing two partial panels.
If you want to remove rust from pots and pans use a gentle abrasive like salt that will scrape up the rust without damaging the metal.
Patch panel rust repair full floor pan vs partial floor pan.
The baking soda will help wick up and remove rust that is in the pan.
After 30 minutes you will want to lightly scrub the rusty surface.