Front wheel done. WD-40 is not a magic bullet. Used a screw driver to scrape off the majority (there was a lot of build-up), then it was a hand-held wire brush alternating with a scotchbrite pad between applications of WD-40 via rag. Finished up with three acetone cleanings, then applied base layer of glue. That took a good 3 hours. Much less build up on the rear wheel so hopefully that won't take as long. Jeez.Lesson to others: Start with Mastik from the get go!