It is possible to pan all the way down to the gold-with no black sands, lead or other foreign materials remaining in the pan. This is often done among prospectors when cleaning up a set of concentrates which have been taken from the recovery system of a larger piece of equipment-like a sluice box or suction dredge.
Panning all the way down to gold is really not very difficult once you get the hang of it. It is just a matter of a little practice and being a bit more careful. When doing so, most prospectors prefer to use the smooth surface of the gold pan, rather than using the cheater riffles. The key is to run the concentrates through several sizes of classification screens and pan each size-fraction separately. Use of a smaller-sized pan ("finishing pan") makes this process go easier.
When panning a set of concentrates all the way down to the gold-or nearly so, it is good to have a medium-sized funnel and a large-mouthed gold sample bottle on hand. This way, once you have finished panning, it is just a matter of pouring the gold from your pan into the sample bottle through the funnel. Pill bottles and baby food jars can make good gold sample bottles for field use, because they are usually made of thick glass and have wide mouth. Plastic bottles are even safer.
Another method is with the use of a gold snifter bottle. This is a small hand-sized flexible bottle with a small sucking tube attached to it. Squeezing the snifter bottle creates a vacuum inside. Submerged gold from the pan can consequently be sucked up through the tube.
If you do not have a snifter bottle or funnel, try wetting your finger with saliva and fingering the gold into a container, which should be filled with water. The saliva will cause the gold and concentrates to stick to your finger until it touches the water in the container. This works, but the funnel method is faster.