I pick mature mushrooms by hand by holding the stem about 1-2 inches from the base and tugging lightly while bending it to the side. This seems to get the whole mushroom and not too much casing soil most of the time. About 5% of the time I have to go back and remove a "stump"
To get the abort I use a three prong "grabber" from an electronics repair kit. Yu can see this in my post "Cambodia LOAF day2 harvest" or something like that. It is yellow and in the foreground on the left side if the pic. It is GREAT for pulling aborts, esp. when the casing is too crowded to get you fingers in.

Shaker