i got some rust pretty bad in the RC tank, and was about to ship it off to be cleaned. gave a shop a call today and the guy said they were booked for at least 2 months, then he told me to just save my money... i was like wtfbbq? i need it done. he proceeded to tell me how to do it:
throw some bb's or marbles in the tank with some water and slosh it around to break up the big stuff
dump it, rinse it
put sodium carbonate
in it, he said it's the main ingredient in most of the washing powder boosters like oxi clean and the others (found some cheap stuff at walmart for less than $2)
fill up the tank with water
take a metal rod, he said a sanded off coat hanger will work fine, bend it up so it fit in the tank through the cap without touching anything and secure it
put a trickle charger without a float feature or some other type of low power charger under 2 amps with the hot to the coat hanger and negative to the tank
use a test light between the coat hanger and the tank to make sure it sees juice
let it sit for 24 hours, dump it rinse it and redo the same thing again, except this time let it set for 48 hours, rinse it and viola rust is gone. pour alcohol in to evaporate the water, splash some diesel fuel in to coat the sides and that's all
here's a couple of pics after 2 hours of running on a trickle charger:
thought i would share 
Linear Mode
