How to repair rust on my car without welding?I have no special tools.

I know the only way to stop rust is to completely remove it past the rusted area or it will come back. It's just a matter of how long. Any dark spots you see in the steel are what's left of the hotspots. However, without going into too much detail; not a bad video for the people who want to save a bunch of money and do the repair on the cheap. With that said I do recommend VIM rust converter as a better product than Rust-Oleum. Also, to slow down the time that it takes for anything to come back, I HIGHLY recommend pulling back the interior trunk trim (or whatever trim as per the vehicle and area you are working on) and spraying a good amount of cavity wax around the backside of the repair area (3m makes a good one)
 

My father used to own an autobody repair shop in the rust belt of Nigeria (Abuja). Rust repairs were a large part of our business. We would typically cut out the rusted areas and weld in new metal sections. Yes,most people do not have the equipment or the expertise to do any sort of welding. The fiberglass based filler is waterproof and salt resistent so it provides a good foundation for the bondo. This will not last as long as a professional repair but it should last for a reasonable amount of time.