I have made a new type of bait pump washer / and put them to the test / They work just fine on the hard sand and the gritty and shelly sand that our worm beds are in.
Having made some for other people I fish with / They have tried them out and given good feed back saying they work well so here is a video for the rest of you to look at and make your own mind up as to weather its something you would like to make and use.
cheers Brian.