Derek Cohen (in Perth, Australia)
Used this way, the chisel will make a release cut - but it will not clear the waste that is attached to the floor of the socket.

If the socket dividing wall (the tail) was thicker, digging into the corner would not be a problem. However, the walls with skinny dovetails are fragile in this area, and it is not advisable. Best to use a (fishtail) chisel that will scoop out the waste and not endanger the socket walls by overshooting.

Regards from Cape Town

Derek