XP 55 (general problems fix up)
This happened back in 2000, right before Vermin War 2.  My trusty XP 55 was all dirty and messed up, I had not battled with it since the last battle of the Freedom Figther Wars in 1999, and it had suffered long time of my irrisponsibility leaving it under the house.  My friend Jacob was over, and he's really good with technical things and mechanics.  Though I'd been battling for about 8 years I'd never really worked on the insides of a Supersoaker.  We first had to run it through a stream of water from the hose, we doused it over and over and over again.  I took a toothpick and cleaned the nozzle out, I was 13, shame shame on a person so old, of course I had gotten mad after Vermin War 1 defeat, but hey thats no way to treat your most loyal weapon.  If your nozzle gets stuck with dirt, toothpicks and a faucet are always good.  We opened it up, and cleaned out the screw holes (dental floss or fishing line works good). 

Pump Problems
Sometimes the rubber or plastic peice at the back of your pump will get stuck in the pumping shaft/tube/pipe or whatever you want to call it.  First of all, take out the pump and don't panic.  I have done this so many times now that its routine, of course I have many extra pumps so I always replace them.  Assuming that you have never done this before  we will atempt to salvage your weapon.  First of all take off the plastic ring shaped peice that holds the pump area to the gun, if it is a guided pump you will have to open the whole weapon.  Now, I reccomend taking a fish hook and a dowel rod, straighten out the fish hook and spear the ending if its stuck at the back, if not get a screwdrier and just pull it out.  I used soap to lube up the walls in one case to make it slide out.