Yeah, they work. We use Permatex at work but any brand will do the job. Get the old gasket as clean as possible, the less oil on it the better. Spray a good film on the gasket and let it sit for 15 minutes, then scrape off and reapply the remover. Do this as long as it takes to get the gasket off. If the spray lands on your hands, wash it off with soap and water immediately or it will feel like you got splattered with hot bacon grease in a few minutes. Not pleasant. If it gets in your eyes you will wish it hadn't.

__________________
83 M-B 300D- daily driver
83 240D gray market
2002 VW Jetta TDI- beater