(Privately Cancelled?) US Mint Stamps -2

I've finally been able to get decent imabes of two of these stamps. Has anyone seen anything like this before? I have about 15 stamps like these. They are MNH. Thanks I apologize for the amateurish way I'm doing this, but this is my first attempt to use this forum. I'm sorry I started this without pictures of the stamps before in my first post. I assure you these are real stamps and the lines are drawn on them (looking from the gum side, one can see the impression through the paper). I also have two stamps with the line from the other direction and the lines are slightly smeared. I have no idea why someone would do this to valid postage stamps.

No apologies needed Bob. Not sure why someone would mark them like that but it won't affect the value too much because there really is no value to them on top of face value. Basically all that's lost is the ability to use them for postage which is pretty much their only value.

Hi Bob.

These lines are not exactly the kind of lines I was referencing. AND.. more importantly, you have now confirmed that you have actual stamps with gum on the back, etc.

I have no ideas about those lines, which don't appear printed on the stamp, and DEFINiTELY do appear to be ballpoint pen or something. Maybe a kid with a pen and a ruler?

I don't know. Good mystery.

Kirk