Very Old Prussia & Germany Help ID Please

Yes I need to hit the library and check out the Scotts but theres so much more knowledge here. Friend dropped off some old world stamps he wants to get rid of . Some look very interesting and may just hit my stock books but I'll start with one inquiry at a time. Can't even make out the octogon cut one so thats a point of curiosity.

Not the earliest Preussen, but old ones. First 1867, CV used 55 Eur (Michel nr. 22)- pmk is probably a railway cancellation (Bahnpost-stempel)-Mainz-Coeln (Mainz-Köln). Try to get more info.

Second, well... if I understood well, can be interesting. It seems, that the pmk is Hamburg (which as far as I know, is not part of Preussen- it is a 'Hansastadt')-but Prussia had a postoffice there. The stamp is not imperforated, perforation should be 11 3/4. (I don`t know, how it`s called this kind of perforation `durchstochen`=`pierced` maybe??). 1861, Michel nr 18. There are 2 shades: brown and greyish brown (can`t tell you this is which) CV for used brown 2,40 Eur, greybrown 36 Eur (approx).

As for color on the 2nd it is actually lighter in person than scan. It is a shade of brown but greyish brown is a hard one. Possibly faded brown if originally brown but very far from a solid brown. Interestin with the details on the cancel. 2 down and I'm leaning on keeping these already.

Second in second row (6 Pfenninge)- 1861 Mi. nr. 15- 2 shades: orange and ..hmm...brownishred (I`ll better give you the german original: mittelbraunlichrot)Used CV orange: 18 eur, braunlichrot: 70 eur. And I guess, I`m finished, because the last 2 makes me a bit cautious - no such shades ever seen, but hopefully there will be here an expert, who can help you. One more thing: the second (Hamburg) pmk seems allright- blue ink was used for example in Brema (Bremen- another Hansastadt, where Prussia had an office).

Wadmalatz Thank you very much for your assistance. I know with very old issues and shades it is difficult to be certain even in hand. I'm thinking the last stamp top row is likely cut but even that I can not be sure of since it is so hard to make out any details.
Here are a few more that may be within your experience. Most look to originally be perfed and either unintentionally or purposely trimmed , Again Thank You

Just bumpin. 2 have been somewhat solved does anyone know any of the others?

I only have a Michel catalogue for Germany. I'd identify the Prussian ones as follows:

Top line: Michel 22 (1867); 18 (1861); 17 (1861); no idea - I can't make out the design.
Second line: Michel 16 (1861); 15 (1861); I can't see a listing fitting this one; and, last, 18 (1861) again.

The second lot are all North German Confederation. Some seem to have been rouletted, others perfed. In order, we seem to have Michel 5, 10, 6, 9, 2, 3 or 15, and 4. All were issued in 1868, unless they're perfed (these were issued in 1869).

These stamps are not especially valuable unless they're imperforate.

However, ones on very thin paper (under 0.05 mm) are also more valuable.

Sorry Jimjamtwo, almost right.
But, The correct North German Confederation Michel #'s are actually: 17, 10, 6, 9, 2, 3, and 16

These all need to be checked for known plate flaws! They can change a $5 stamp into a $200 stamp.