When using a sluice box, you will be able to process a lot more material in a shorter amount of time than you could accomplish with a gold pan. This means that your sluice box can accumulate a large amount of black sand and hopefully gold in a short amount of time. Failure to clean your sluice box regularly can result in lost gold as the riffles can become so bogged down with heavy concentrates that the newly added gold bearing gravel merely washes out of the sluice about as fast as it is added.
So how do you know when it is time to cleanup your sluice box? Generally, I like to cleanup when black sand begins cover much of the top three riffles. If you can no longer see some of the riffles and instead you are only able to see black sand, then this is bad.
It is hard to say how often you should cleanup your sluice box because every location is different. Some gold bearing rivers have little black sand and other have large amounts of heavy concentrates. In the first type of location you may be able to sluice for gold all day without cleaning up, but in the second type of location you may have to cleanup every hour or two.
When cleaning up your sluice box, the first thing that you need to do is set up something to catch all of the contents of sluice. This can be a gold pan, a bucket or perhaps one of those black plastic masonry tubs. I prefer something deep like a bucket which makes it more difficult for the concentrates to splash out of.
Next you will need to pick up the sluice box slowly and keep it level. You want the water to drain off the lower end of the sluice without washing out much of the material in the sluice.
Then you will places the lower end of the sluice into the bucket, gold pan or other container and tip the sluice up at an angle. With another gold pan or small bucket, pour water into the top of the sluice to wash out the bulk of the gravel and concentrates. Now you can unlatch the riffles and lift them up. If the riffles come out completely, be careful not to knock the material off as gold may be stuck to it. Rinse the the riffles off into the bucket and then set it aside. If it is attached to the sluice, rinse them off and then lift them out of the way.
Now carefully remove the carpet or miners moss from the sluice and keep the whole thing in the bucket and then pour more water down the trough of the sluice to rinse out the remaining concentrates. You may need to scrub off some clay buildup which may have caught some of the gold.
After removing the clean sluice from the bucket, it is time to clean the carpet material. Carefully grab each end of the carpet and while keeping your hands close together, lift up the ends of the carpet. As most of the fines will be in the carpet, be especially careful to keep the carpet in the bucket area so that any material that drops off will fall into the bucket.
At this point, the carpet should be in the shape of a “U” with the middle sagging into the bucket. Lower the carpet until the middle is submerged in the water. Carefully lower one end of the carpet while lifting the other side so that one half of the carpet passes under the water. Repeat in the opposite direction. Turn the carpet over and do the same thing to the other side of the carpet. This will allow the heavy material to fall out of the carpet and end up in the bucket. Repeat the process until the carpet is clean.
Now you have a choice, you can either pan down the concentrates to collect your gold or you can dump keep it in the bucket and cleanup later. I prefer to maximize my time when gold prospecting so I prefer to save up all the concentrates and clean them up at a later time.
Finally, you can put your sluice back together and get back to sluicing for gold.