with alot of elbow greese i put mine in a bucket and filled with water mixed it a bit then tipped water out i did this for about 2hrs its hard work but once the water starts to clear in the bucket you know your getting somewhere, its well worth it the fish love it and its easier to clean
i did mine in the bath purely because i could use warm water as my hands were freezing, but some who are braver do it outside with the garden hose, as the sand sinks in the bucket its only the water on top you tip away
No need to wash it at all. Fishaholic one of our members has kindly put an awesome video up on another link on here to show you how to do it - click the link below. (second thread on the page). It will save you hours of work!