I have done 2 seats with great results both red and purple have gone black well for me
Like this
2 round tins of Dylon ( the ones for nylon) woolworths by the shoe polish
one bucket
1 seat ,
shit loads of salt , normal table I used a big bag
put seat in bucket and puncture the tins add them to bucket
cover seat in boiling water
add salt
dye will come out the tins and dye the seat
stir , poke. look,turn over , add some salt for luck , add more boiling water for a laugh and generaly enjoy your manly back garden science.
and leave for a couple of hours
hey presto black seat, the gold is still there,so is the kashimax rear reflector sticker
Rich