Tan dash help!

  1. My model of MX-5 is: NA
  2. I’m based near: Hampshire
  3. I’m looking for technical help or recommendations on: What to use to get the tan dash revealed.

Scraped most of the black top off with a knife (carefully) now stuck trying to get the rest off and out of the grain. Using white spirit/meth with wire wool, scouring pad. Can’t seem to fully clear up the grain.
Is there any tan vinyl paint or dye people recommend also?