CRC Gasket Remover - WOOB
 

CRC Gasket Remover #05021

Pro: Cheap, easy to use, does the job well
Con: Takes awhile to work, stubborn gaskets still need scraping

Ease of Use: 9/10 (-1 for needing a razor blade on some gaskets)
Quality: 10/10
Value: 10/10 ($6.19 at Oreilly's for a 12oz can, much better than $10+ for 4oz of Permatex stuff)
Overall: 9.7/10

When I needed to correct a boost leak on my 20B-REW and the turbo Y-pipe gaskets didn't want to budge after 20+ years in place, I got some CRC Gasket Remover from the local Oreilly's. It says to spray on and leave sit for 5-10 minutes, so I tried that. Made no difference. Sprayed more on and gave it half an hour. It softened them enough to gently scrape off with a razor blade. On stubborn ones, let it soak for an hour or more. The last one I did was on the rear turbo's outlet. After soaking for an hour, it slid right off.

And last, be careful with a razor blade. I cut myself a couple times in the process, but thankfully it wasn't too serious.