Germany 1880 - What's Happened To This Stamp?

A lot of old German stamps (mostly pre-1900) I bought recently contains a few that are really in such shocking condition that I can literally think of no explanation for what has happened to them.

This one is not all that bad, but I'm curious to know what people think might have caused this kind of damage, particularly the big line down middle. Was this stamp printed like this or damaged afterwards? If so, how?

And one with even more lines:

The second certainly looks like what the Australian George V collectors would call a tin shed job.

lol@tonymacg.

But, really, has anyone ever seen stamps like these before?

They look like they've been scraped, but they have not (there's no surface damage - they are smooth and utterly normal to the touch.

I have no idea what to think.

There are a few German issues pre-1889 (including some Mi 42 issues) that were printed on a chalky paper designed to prevent re-use. These issues tend to be very water sensitive, and large color loss is not uncommon. That may be the source of the damage.

Thanks for the suggestion, PostmasterGS. In each case it does look as if an attempt was made to eliminate the cancel, but that process appears to have damaged the original stamp as well.

Here's an Australian stamp that seems to have been subject to the same kind of treatment: