Quoted from Mr_Tantrum:
Would you mind detailing the process (steps, products used, etc.?). Mine could use some improvement.
If you don't have supplies lying around.. your easiest bet is probably to just buy something like a 3M headlight restoration kit. The concept is basically the same. Start with high grit sandpaper, then continue with progressivly higher sandpaper, then switch to a compound, and then polish. Essentially.. rough grit to smooth grit.. just at very high grit levels. Each higher level smooths out the scratches from the prior level. It looks scary at first, but as long as your levels are good enough, anything can be taken back to gloss.
I think the 3M kit has a 1000, 1800, then 3000 grit pad with compound fluid.
My dome was really oxidized and hazed.. and didn't have enough material left from my last headlight kit, so I just used regular sandpaper, hand sanding, and machine applied compound/polish.
I think I started with 1000 grit. Wet the paper liberally and the dome a bit (I have a small spray bottle of water I use). I sanded by hand, in straight strokes around the circumference of the dome. Just work on a bit top to bottom.. rotate.. repeat till you get all the way around. Your goal is to get a UNIFORM finish at each stage. You shouldn't see deep patterns, gouges, etc. Keep the paper wet, and flush away the slurry as you go. The water makes the paper slide better and it keeps it from gumming up. Be liberal with the water. You'll see how much easier it makes things. Complete a pass around the sides and top. Remember... uniform looking is your goal. The lower grit sandpaper will create QUITE a bit of mess/slurry.
Rinse/wipe all the slurry away with a soft rag, then move to the next higher grit sand paper. I went, 1000, 1500, 2000, 2500. It only took like 5-10mins tops per grit, so I was generous with the levels I went through.
I took some photos as I went stage to stage.. so you can see how it progresses
After about 2000 or 2500 grit.. you can move to compound instead of sandpaper. I use Meguiars compounds and polishes.
I started with Mirror Glaze 'fine cut' cleaner #2.. which is 5 on their cut scale. Used a foam pad with a drill attachment and clamped the dome to my bench.. then just worked my way around the dome. It's a bit tricky given the round cylinder.. but besides hitting the the backing plate to the plastic.. you can't really hurt anything. Reapply to the pad whenever things start drying out or you look like you are dragging material vs applying it. Again, just work around, trying to make things uniform. It will really start to clear up at this step. Wipe it down with a clean soft rag after this step to remove all the excess compound. You want to use a machine to apply this stuff if you can.. as it really needs the rotary action to be effective.
Then I moved to 'swirl remover' #9 which is a 3 on their cut scale. Using a clean foam pad, on the same backing plate/drill attachment.. worked my way around the dome. Just wiped it up with the microfiber towel after that.. and finished.
Since this sits so far from the player... you don't have to be perfect. For the inside, I just wiped it out.. didn't even bother polishing.
The Meguiars stuff can usually be found in your local auto store, but finding the higher or various cut levels can be challenging. I don't remember if fine cut I found local, or had to go online for. Walmart suprisingly has a good selection of the 3M and Meguiar's products.
The high grit sandpaper is easily found in small pieces in the 3M auto supplies. Cheapest I found was walmart.. they sell an assortment pack even that is perfect for these smaller playfield and plastic applications.
Less than $4 gets you a pack of 1000, 1500, 2000, and 2500 pieces - https://www.walmart.com/ip/3M-Wetordry-Automotive-Sandpaper/17130294
Pickup 2 and you'll be set for numerous projects.