Suppose I need to replace old concrete on a driveway or in any similar scenario.
The usual way is to just gather all the old concrete and dispose it to a landfill, then buy cement, sand and crushed stone and prepare new concrete (or just order already mixed unset concrete). This is not very convenient - disposing concrete can cost a fortune and also buying and moving in new crushed stone is not free and one might also be concerned about environmental impact of those operations.
It would be good to try to reuse old concrete as crushed stone. The number one problem is that old concrete fragments from a driveway have lots of dirt on them - mostly all kinds of ground and also whatever could get attached to them while the driveway was in use like oil, paint, other contaminants. Obviously using dirty stones will lower concrete quality singificantly.
Is there a simple yet reliable way to clean all those concrete fragments so that they can be reused in new concrete?