Using the time it takes to get some other stuff done to take care of the rust in the tank.  Holy bananas the gunk that came out. Been about the fourth time I've cleaned it. This time I did a week of vinegar,  screws,  rinse, pressure wash inside, then the por15 by instructions. Cleaned up the gas cap real nice too. I hate that I never remember before pics but I'll add a couple of Midway thru ones

Looking good! i used to use vinegar but got tired of messing with it. Now i just take it up to the local sand blaster, blast the whole tank myself, blow it out good, wash it out good and paint it. Sadly the tank for my 75 DT250 has a bunch of pins holes so im fighting that.

The vinegar makes a mess, that's for sure. I can see where sandblasting would do it..