cannot get varnish out of my bike's gas tank!

[myBadVarnish]

I've used almost 1 gallon of Lacquer thinner, and while a lot of the old varnished-up gas came out of my motorcycle's gas tank, still a layer of 'hard tack' varnish sediment is adhering to the gas tank's innards like a tick on a mule's hind parts.

So I want to use a pressure washer, but my house pressure washer being strong enough at 2300 psi doesn't have a tip that is bent in such a way to get inside my bike's gas tank.

AND WHAT CHEMICAL, OTHER THAN LACQUER THINNER, DO I USE?

I'm hoping you guys can bail me out, I really want to use this gas tank again!!