I did mine with toothpaste and it was a dismal failure, they were still cloudy but just smelled of mint.
You can buy the kit from ebay but I bought mine from Carrefour in Alicante (about 15 euros). It takes about half an hour per light and is very simple. You do need the sealer wipe which comes with the kit to give clear finish. I've done my headlights three times each.