Paint Brush Trick

Let me start with the disclaimer that this is not my idea and I don't remember where I read it, but I recently tried it and it works.

I was painting some rusy metal window frames, and when I was done I knew I wanted to paint another rusty item (a tyke bike, basically a pedal-less tricycle) that serves as a decoration in my flower garden. I didn't have time then but remembered reading that wet paintbrushes could be frozen to preserve them and use again. So even though I was using a cheap paintbrush (more on that later) I decided to try it and wrapped it in plastic wrap first and then put it in a ziplock bag. I put it in the door of my freezer, well away from any food. It was probably a week later that I got it out and tried using it. It only took a couple minutes to thaw out and then it worked just fine to put primer on the tyke bike. Then, because I was working in the garage and noticed that the very annoying floor-to-ceiling center support pole was also rusty, and also used it on that.

Re the brush -- I mentioned I was cheap, and let me tellyou how cheap. This brush I carefully saved to reuse was one of a three-pack I got at the dollar store. But I figured, why should I waste another brush if freezing would work, and if I didn't, well, I already had the plastic wrap and ziplock bag on hand so it wasn't costing me anything extra to try it....

Let me finish with a question: why does Rustoleum, a brand I like and trust, make their rusty metal primer in a rusty brown color? It ensures that no matter what color you paint over it with (unless that color was also rusty brown, and why would you do that?) needs two coats. I have spray painted the tyke bike red (which is was originally) and painted the support pole black, and both will need another coat. Why couldn't they have made the primer in some easy-to-cover color, tan or beige or white even? Is it part of a conspiracy to sell more of their paint? Don't they realize that just because you used their primer doesn't mean you're going to use their topcoat (I did, except for the spray paint, but still....).