For as much as you spend on supposed cleaning and treatments , you could have bought a new moped . LOL
OK maybe not a new moped . ;)
For about 7 bucks and a couple days waiting , I'll stick with using oxalic acid .
Here's the write up with pics Ryan mentioned :
https://www.mopedarmy.com/forums/read.php?6,4160423,4160423#msg-4160423