A few years ago I made a little tutorial for a DIY freestyle palette using tins. Recently, I wanted more freestyle palettes to house my Inglot shadows (I like how their Freedom Palettes look but the general consensus is that taking shadows out to switch around is a huge pain in the ass) and my recently depotted Urban Decay Book of Shadows UD♥NYC. I also wanted bigger palettes that matched my MUFE and MAC ones, I am particularly drawn to black palettes.
I started out by ordering a empty palette from eBay. This one was like $4.50 including shipping. I bought one that held 10 36mm shadows.
As you can see, it is the exact same size and dimensions of those 10 MUFE palettes. They used to give these away for free if you bought 3 MUFE shadows or blushes at Sephora. Sure wished they still did! The only difference between these palettes (well outwardly appearance, anyhow) is that the MUFE has a matte, almost velvety texture while the cheap eBay one is just regular plastic (slightly darker in color and not quite as smooth in feel as the old MAC palettes, in case you were wondering).
All I did was to rip away the insert which is made of thin, really pliable plastic. There is glue at the bottom of the plastic which is rather annoying to remove. It took me a while to scrape this goo off, even with rubbing alcohol and a putty knife. Next time I'll try Goo Gone to see if it works better.
When it is clean, apply adhesive magnetic sheets. you might have to clip a small rectangular shape out so that the sheets fit near the closure. You can buy these sheets at Target, Walmart, near kid's craft supplies or find them at office supply stores (usually for turning photos into magnets). If you have a lot of MAC Pro pans (where there is already magnets, which do not stick all that well to the magnetic sheets) then you might consider making it a reverse palette. You'd have to buy thin sheet metal and shears (home improvement stores), cut it down to size and adhere it to the palette. Or you know, just rip off the magnets.
This palette holds shadows pretty well. I can flip it upside down and shake it and they won't fall off. However, dropping the palette on the floor will probably cause them to fall off (ok, not probably, I know this from experience. That's how my palette got a little dusty with shadows already!).
Hopefully you found that useful, if you were thinking about making freestyle palettes yourself that looked sleek and black.