Odd Perforations? Help To Identify?

Going through the collection I bought I came across an envelope labeled CH 8 1/2 + Special. I see the perf 8 1/2, unfortunately it looks like one side of it is ruined, bummer. The other stamps however I haven't seen before. Any help on these? Thanks! Edit: I know the second stamp second picture is CH 10 badly off center.

The Chicago precancel has 2 slots that indicates that the stamp was processed through a Schermack Mailing machine. The Schermack Company built a machine that affixed stamps to and sealed envelopes at a rate of up to 250 per minute. The slots weren't perforations as such. They were used by "fingers" inside the machine to locate the stamp prior to it being cut from the coil by a knife.

The Schermack Company used imperforate stamps to make coils of 3000 stamps that were used in the machines.

Agree - Chicago has Schermack type III slots
The pair is from a booklet pane
The remaining singles are from coils which passed through an affixer with its knife blade slightly out of adjustment, leaving the stamps cut a bit off their perforations, and considered damaged.