A friend gave me his 15 years old MBK Super Mistral, which I plan to convert to single speed and use as a beater and commuter.

I replaced the brake pads, and am already riding and enjoying it, but what bothers me is that the frame has some rust. I may get to sandblast and powdercoat it in the future, but right now, since it's going to be a beater, I don't care about the look, I just want to keep the rust in check.

I thought about sanding it down and then applying some lacquer over it, but going to the nearest DIY store today, I saw some rust remover products (such as this one,) and wonder if they'd be OK to use on the frame? (the tubing sticker says "707")

Is there another cheap, and not-labour intensive way to handle the rust?

I know this question must have been asked before, and I did try searching the forum, but I couldn't tell from what I found if it's the same stuff as described in other posts. Please, help a C&V noob.