[dvldoc]

The most common debris are little pieces of plastic from were you drilled on a new tank or crap that has just been collecting in the tank over the years, It may not appear solid when you look into it but just might be gummed up at the bottom this stuff can collect in a nice little ball and get pushed through the system

When I do a install I drain a stock washer fluid tank and flush it out with a high pressure hose. If it's easy to remove then I do it with it off the vehicle. Limeaway or similar products works great for getting it looking like almost new on the inside But Limeaway is my choice for cleaning washer fluid tanks, 6 month pump flush, and nozzle filter cleaning. Just fully flush out everything before connecting back through the vehicle.