[R6Ruckus]

That's some awkward stuff that I wouldn't want cycling in my fuel system; just keep scouting ebay for cheap used tanks.

But to keep you rolling down the road, pretty sure the best option you have is a fuel system safe cleaner (more fuel is typically an effective option) and some awkward shaped brushes

 

[R6Ruckus]

EvapoRust with some nuts and bolts thrown in and shake till your arms feel like they’re gonna fall off.

I actually remember hearing this before, at least do some research down this path

 

[R6Ruckus]

You can potentially retrofit a fuel pump strainer, but with enough diligence; I'm sure you can get it. Just go to the hardware store and get pipe cleaners