Take a sponge with a scrubber and scrub at all of the rust spots using the heavy duty scrubbing side.
Rust removal floor pan.
The baking soda will help wick up and remove rust that is in the pan.
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.
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.
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.
Patch panel rust repair full floor pan vs partial floor pan.
To scrape off the rust cover the bottom of the pan with a thin layer of salt and scrub it in using a brown paper bag until the rust is lifted off.
The floor pan is such a large area i had to tackle it in three sections.
Then make sure you properly seal the floor pans.
Alternatively soak the pan overnight in a solution of water.
The front where the pedals are the middle under and behind the front seats then the section under the rear seats.