How do you preserve your paper money? Specifically, what should I do with an old over-sized bill that I have that is really fragile?
I think Mike nailed it but be careful putting it in the holder. Another is a Capital holder that many coin dealers carry. A bit pricey but well worth it if the note is worth that much to you.
I use currency sleeves and try to keep the notes in a place where I can keep the temperature and the humidity under control. See's presentation is very informative and having been to Singapore I can see where you would need to do that to keep your notes in top shape.