 Normally, it used to be done by using a stream of distilled water from a wash bottle.However, such a way is ineffective because dense precipitates may become compacted at the bottom of the beaker or, in the case of light precipitates, may become dispersed on the walls of the beaker.Therefore, by using glass rod to take them off may result in poking a hole in the bottom of the beaker or scratching of the beaker wall.