I replaced the air filter in my car sometime ago as part of a minor renovation. I was going to throw the used one away but held on to it as I figured the circular shape with the holed patterns would make for an interesting DIY project.
I finally got around to working on it this weekend.
The first job was getting rid of the filthy paper filter. I removed it with a sharp paper cutter and cutting pliers. It took a lot of effort to get this done as the cloth/paper material was not at all easy to remove. The sharp edges on the cylinders weren't helping.
After removing the paper, I cleaned the whole unit thoroughly with a brush and some alcohol. I also gave it a nice sanding to bring back the shine but this would later prove to a be a waste of time.
After I noticed there were too many imperfections on the surface and the leftovers of the paper filter were all over the place, I decided to give the whole thing a coat of matt black spray paint.
And oh, the grill I used in the middle came from an unused exhaust fan. I cut the grill to size and secured it to the air filter assembly using loads of glue.
Finally I installed the bulb assembly and a yellow 15w bulb from my bedroom and here are the results: