Hey mu50stang...
Klondike here....
Here is something I built several years ago and used it often.....I no longer have any pictures of it, so I'll just describe it to you.. it will sound funny.. but it was very effective.
First thing, screen the cons to 1/4 inch or smaller...
Second... find a used utility tub at a garage sale.. or buy one new, but they are kind of spendy new....
Next ... within a inch or two from the top and next to a corner... cut a hole with a hole saw.. and securely mount a 1/2 inch pipe...screwing on a valve to control water pressure and flow... On both ends, screw on an adapter from NIP thread to water hose bib..... On the outside water connection, connect a water source from either a faucet or a fresh water pump...
On the inside water connection, connect a small flexible hose, about 2 feet long...
For the drain, use several, 4 or 5 washers under the flare of the drain pipe and tighten securely.... then attach a 90 degree drain pipe out to about 2 inches past the outside wall of the utility tub...
The using 2 easy panner sluices or equivalent... stacked back to back into one long sluice.....I built a simple wood frame for the top mounting and bottom mounting of the sluices, so the top most part of the top sluice was just under the extended drain pipe.. be sure to flatten the drain pipe end some. it helps spread out the water flow...
With the washers under the flare of the drain pipe inside the the tub bottom, causes a small lip to appead, forcing anything washed to have lift up and over to escape the tub....
Now turn your water on, adjust your flow with the valve.. and begin to shovel, slowly your cons into the tub.. the water will cause everything to "whirlpool" around and around..washing the lighter things over the lip of the drain and into the drain... the sluice boxes are just there for extra security for anything that might be washed over the lip....
With a little practice and using this contraption, you'll get the hang of it....it works very well.. and you can go through cons rather quickly...
It is inexpensive to build, light weight ... and works well...
Good luck...
Klondike...