Often, following a crop disorder, there will be a small lump of material left in the crop, especially with older chickens. I've found that this eventually goes away. But you can encourage it by massage before the chicken eats. This may break up the material and it also helps stimulate appetite which in turn helps push material through the crop.
In other words, be patient. The crop will eventually clear.
In other words, be patient. The crop will eventually clear.