Markings On Back Of Stamps

I was able to plate, 9L3 - 99L3! The 9th column of plate 3. Plating these stamps is not really an astonishing philatelic accomplishment. The Chase book offers images and descriptions of each stamp in the row. Members here and the Steven Ruecker site helped confirm my findings.
It is astounding that I own a collection that included these stamps...

Anyway, I needed a break from plating. So I was having some fun checking out the back of a few. Thought I would post some. Maybe members can identify some of these markings.
The first one I included, because, I believe the plate markings are correct, 100L3. You can see by the size of the stamp, it includes right side and bottom selvage. I enhanced the colors so the pencil could be seen better.






The one below reads, HC VQ. There are other stamps in this collection with similar markings. I pulled this one because of the wonderful SON paid 3 in a circle cancel. Wanted to get this one into a mount.


The one below I have already placed in a clear mount. I believe these are Chase plating notations.

The dual purple fleur-de-lis are likely owner's marks or expertiser's marks.

CC, there kind of neat. I thought they might be a dealers mark. Hoping someone here has seen them.
I have a couple others hand stamped in blue ink, they read J.Schle or maybe Schli.

Etats unis is French for "United States." I have seen this written on many US stamps and blank album pages in collections formed in France. I don't think it points to a particular user.

Nice catch, essayk! I speak some French, and didn't look close enough.

These backstamps can reduce the value of a stamp, especially if they bleed through to the front as on this US Scott #37 which has two stamps:

Classic Coins - Have you dipped the stamp to check for added margins?

stampcrow - Isn't some clean up in order? Almost all used US stamps can be soaked to remove hinges and dirt.

Clark

I haven't. Is there one margin in particular you suspect is added?

Thanks essayk!



cfrphoto, true enough... but, I don't have any sophisticated tools for doing it, ie a drying book?. I'm concerned about wrinkling (scared).

Another factor, there's over 950 of these (or lazy). I've only removed about thirty stamps, from the pages, so far. As I move forward with these, I think I will heed your nudge and soak em as I go.
Luckily about 80% have only the one hinge.

Classic Coins,

No smoking gun, but the left margin seems to be fairly large. Looking carefully with a 10 or 15 power glass, start in the upper left corner.

Clark

No chance the #37 has an added margin. I just checked with a 16X loupe, as I did when I bought it. Nice distribution of fibers.

I knowingly bought a classic US stamp with an added margin about 15 years ago because the price was right, so I know how to recognize them.

Before the internet and when we couldnt see the stamps it was not unusual for mail order dealers to place a small stamped mark on the back of their stamps in case of returns they would know they were getting their stamp back and not a switch.