Notgeld I Bought On Ebay Was Practically Ripped In Half

The question of "repairing torn notes" is a complex one for banknote collectors. The number one issue must be, to try to have the same mindset as someone who's taken the Hippocratic Oath, and Do No Harm. Watch any of those videos about restoring fragile ancient or mediaeval artifacts (such as paintings) and you'll find that most of their efforts go into not actual conservation of the original artifact but in undoing previous conservation efforts by well-meaning previous owners. We don't want future owners of your note cursing your bones for your carelessness in causing stains and further damage.

You want to avoid anything like regular stickytape that will leave a sticky residue behind on the note; this will not only look ugly in coming years but may damage the paper and would be difficult for a future conservator to remove. There are "document repair tapes" you can buy that are "safer", and have been designed with preserving historical pieces of paper in mind, and feel free to experiment with these if you wish, but even these are still not necessarily "safe" for every possible situation. For a banknote, the Do No Harm principle is perhaps best observed by the approach you've already taken: put it in a rigid archival plastic holder, so the note can be picked up and examined or photographed without worrying about the tear getting worse.

I own a damaged Republic of Texas note that I keep this way. The note is quite thin and fragile, and appears to have originated from the New York bank vault cache of Texas banknotes which had all been cut-cancelled (a fact which was fully disclosed when I purchased it). A previous owner of this note has attempted to reinforce the cuts with thin strips of document repair tape, which does not seem to have caused detrimental effects thus far. So apart from taking it out for photography purposes, it stays in its rigid plastic holder. The rigid holder then goes into my regular banknote album.