The process I was taught was to suck up a 5 gal bucket of water than let it drain to wash rocks out of hose than suck 5 gal clean water followed by a Sponge Ball But recently I got a new 38meter 5 section  Schwing been having problems getting ball back  when I take it apart I find a wad of washed rock . Any suggestions?????

what kind of sponge do you use? We use 9" square ones wet them up good and push them up in tip elbow rinse your tip hose with water and start sucking it back. no need for extra water in pipe i have been doing it that way for almost 20 years never a problem. we have 2 38-5 

If you have them or can get them. Get yourself a soft sponge ball, and a hard ball, the good orange kind that you can't blow air through. Then connect them with a length of rope. Run it through both balls with a large washer and a tight knot on both ends so they're 18" (or so) apart. Don't bother with sucking up any water before. Push the soft ball into the tip elbow first, then pour a few gallons of water, then put the hard ball and pull em back kinda slow.