Degrease is key. I'd even go as far as using a non-wetting cleaner (eg: loctite primer, elect contact cleaner, etc). Loctite needs reactive metal contact and a lack of air to cure, so the cleaner the better.
There are a couple wicking compounds you can try if the cog is on too tight to remove w/conventional methods.
Wouldn't use red, though. You need heat to remove that stuff, and with an Alum shell and steel cog, the shell will swell into the cog threads when heated, making it near impossible to remove w/o damage.