Aborts are fruitbodies that for some reason cease to grow and never reach maturity.
They can be recognized by their blackish heads and the fact that they stopped growing at some point. Still they are good to use unless they are rotten.
When the cap is roten, it is very soft, sometimes smelly and detaches very easily from the stem. If the aborts are in such condition, discard them.
Allways pick all aborts after a flush is over.
The aborts in the picture are still good to use.