All my bikes and pointless upgrades: Fairlight, Stooge mk5,

Secret sauce you say ?

Ketchup, mustard, mayo diced pickles and a wee bit of vinegar. It's delicious.

If that doesn't work then try caustic soda instead!

I used the brand Amway oven cleaner. It's pours out in a pretty thick gel.
Any oven cleaner that has a high sodium hydroxide content should do the job.

Its nasty stuff though and could damage alloy parts if left on for too long.