Removing gas tank varnish

Hi,
I dropped the tank on my '96 Tacoma 2wd today. There was about 7-8 gallons of terrible old, nasty varnished liquid (I think it used to be gas). Once I drained that out there was a lot of pieces of varnish at the bottom of the tank. Fuel pump was covered in varnish/rust. I dont think that the tank is too rusty but it definitely has a little bit of surface rust inside. What is the best was to clean this old varnish out? I might try electrolysis to remove some of the rust, could that remove the varnish as well?

Thanks

 

Old school. Back in the day we would dump pebbles, get them at Home Depot or the like, in the removed tank. Them roll it, shake it around the yard. The pebbles would loosen rust and yarnish up. Then dump out and rinse. Might still work.

 

Muriatic acid! wear a respirator and some serious gloves, it can make rusted chrome not look like it ever had rust. Use some three o steel wool with it. Do it outside the garage.

 

call around to some radiator repair shops and see if they can do acid washes for fuel tanks

 

Ok, thanks for the ideas. One question I had though was does anyone know what kind of plastic they used for the bucket inside the tank to cool the fuel pump? I dont know if that could be damaged by acid?

 

If it,s just surface rust:
Remove varnish first then proceed to remove the rust
Pebbles trick is a good idea to break down the stuff inside the tank
Then lacquer thinner will work for the varnish
Then for the rust, acid wash (by shop or DIY)

If you do it yourself, use phosphoric acid. Don't do muriatic, it's for big heavy rust and if you're not familiar with it, don't

I can't answer your question apout what kind of plastic it is, but I think it would be best to clean the fuel pump separately. Let it sit in thinner to remove varnish, let it dry, then wipe it with an acid soaked cloth or rag

if it's big heavy rust, you better change your tank. You can try to save it, but you will have to change it eventually

 

Yeah it looks to me to be mostly surface rust, not all scaley and thick. Plus a brand new tank is $200. I guess I could find a used one cheap somewhere but I would rather save this one if possible. It doesent look too bad to me.

I plan on cleaning the fuel pump seperately. However the plastic tub to hold the gas to cool the fuel pump is built into the tank. No way to take it out. I just dont want to accidentally mess it up. Carb cleaner might cut it and leave the plastic intact but I am not sure about acetone or acid.