after a quick google, it throws up
turps substitute/synthetic turps
Pure silicone spray (hardware store), it's water proof, and cleans without staining, use it outside to clean the clothes as the overspray may land on the floor making it very slippery.
this from a pvc inflatable boat type website
From a how do i care for my goth clothes site
PVC
There are several ways to clean PVC. Most of the time I'll just use a little Febreeze on the inside to freshen the item up, but if it is really soiled you can hand was with Woolite in cold water. Never put it in the dryer or use a blow dryer to speed up the drying process. Actually, never use anything hot on or near the stuff because it can melt ,and the fumes from burning or smoking PVC are very dangerous.
And never, ever, ever get organic solvents on PVC. Nail polish remover is death to polymer. (I'd be dodgy about permanent markets, and nail polish as well.) PVC gets swollen easily with acetone, and then goes white and flaky.§ 3
Once you have it cleaned you can use a little Son of a Gun or Armor All on the outside to shine it up and you're ready to go.
the only other option is dry cleaning....just tell the staff they are outfits for the rocky horror show production you are putting on