I may be replacing my fuel pump this weekend, if I do I'll want to clean the tank out.

What kind of cleaning agent should I use? Anyone have any tips on this?

You will most likely find the tank interior pretty clean ... assuming you've been running at all. Most of the small stuff will have already found the pump inlet screen and will be on it. Of course, you may find some alien large parts tumbling around that can be picked out. Kids toys and such ...

What little else will come out by with a wiping around the pump area tank bottom using clean shop towels. You will not need any "agents".

Great, thanks for the tip.

The best agent to clean the fuel tank is gas.