sterilizing fuel tank before adding e85
 

what can i do to get all the crap out?

drop the tank and use hot soapy water (detergent or degreaser like simple green) rinse well and dry thoroughly.

what crap? you got crap in your fuel tank. hmmmmm guessing you have filled up with dirty fuel at some point. not good, a freind of mine did that and the engine blew up :(

Best way to clean a tank is to have a radiator shop steam clean it. Not particularly expensive, but a lot of radiator shops no longer do this, so you might have to look around a bit.

Second best is to drain it, wash and rinse it with mineral spirits or similar, then use a tank lining kit to seal the tank up. This is done all the time with vintage motorcycles, so the kits are easily obtained and not expensive, although obviously you will need a large one or several small ones. Follow the directions of the lining kit and you will have no issues, although BEFORE you buy it make sure it is compatible with E-85.

Any way it goes, the tank is coming out to be cleaned. If your tank is not that bad, you can simply make the switch to E-85 and be prepared to change fuel filters many times. Even if you clean the tank, any varnish, sediment, or residue in the fuel lines will find its way into the fuel filter. as E-85 breaks it down. I advise strongly to put a filter immediately before the fuel rail and to change it very often during the first period of use with E-85. Also be aware some people have experienced a weird "gummy" deposit at the injector nozzle using some blendsof E-85 that seems to be a large petro molecule precipitating out, and this can clog the injector nozzle and cause issues. Be prepared to pull the injectors regularly to inspect them after the changeover.

Meh!... I switched to E85 and didn't do a thing to my fuel tank except drain as much gas out of it as possible.
Checked the filters a month after making the switch and they were as clean as the day I installed them.

I know a lot of people who have done the same thing, including myself on a couple of different cars. Some guys have issues and have thier filters clog, other guys just sail on through without any issue at all. Since we do not know the history of the car, its risky to advise him to just throw some e-85 in and check the filter once in a while, but hey tats up to him if he chooses to take the risk :)

normally if tanks are bad its obvious.. if you take out the pump cover and the insides are peeling and or rusting, or there is a large amount of sediment and deposits, cleaning is advised.

product = fuel set ,, see if you can find it in your country

the inside is pretty much fine on the tank other than the fact that the body shop was supposed to tape up the fuel pump opening from the body dust but sadly it made it in. so I dropped the tank and rinsed it with water. the residue comes out with some scrubbing with a scot brite brush but i can get it all out because i cant reach around the baffels. I think i may fill it with some e85 and just see what that does for it.

Does the tank have to be 100% rust free? Cus I'm on the process of switching over and my tank has minimal sediments and little rust directly under the fuel pump assembly

it doesnt HAVE to be since that is the purpose of fuel pump socks and fuel filters but removing contaminants is always a good idea.