Ok My Process is:
Never use any alcohol based or harsh strippers like brake fluid products on PVC (Plastic) it will eat it alive, hardens and shortens up the ageing process:) always use a water based product, like a citrus 3M organic based paint strip.
Better yet, don't paint plastic, it looks shit.
Restoration process: Depending on the gauges and decay of the PVC will depend on how you much time you spend on each process.
1. Using 400 grit sandpaper ( Dry), sand back until mat finish, smooth and all gauges are gone or relatively gone, so your happy with the finish (I use an electric hand sander) . You can get a plastic welding kit or filler if your keen, but if your going to go to that extent
www.plasticrenovations.com and contact me i'll get you a quote for restoration.
2. Using the 400/200 grit, start the wet and dry process and keep working until all smoothed out and stats to get a gloss, LIGHTLY apply heat via heat gun small sections at a time (this makes the molecules in the PVC fire up and start to rejuvenate)
3. Buy a Novis 1,2,3 pack from American eBay, ($50 delivered to your door) or if you can find equivalent in Australia let me know, i'm yet to find it! and polish the hell out of it, repeat stages as required.
4. Purchase a really good quality car polish (Maguires) from Autobarn and polish until a high mirror shine:)
Its time consuming, but it's worth it in the end:) Happy Polishing:)
My suggestion is, restore and old shitty piece first, as if you make a mistake with the gun, you wont be in tears!!!!!!!!You can use acetone to seal the inside of a tank, swish it around and with a few nuts, bolts and screws to loosen and shit caked on the walls:)