re-using corks

This question probably gets asked here 82 times a month... but, what is your opinion on re-using wine corks? I'm set to bottle 5 gal of chianti this weekend, but only have 10 or so new/brewshop-bought corks. However, I have about 18 months' supply of corks from various wines I've enjoyed. Just wondering if:

1. it's a good/OK idea to re-use corks
2. if there is any special way to sanitize used corks
3. any concern with aging wine with used corks, including storing horizontally (leakage?)
4. preference of re-using real cork or synthetic
5. other comments, suggestions... ?

No, I would never reuse a cork. There is no telling what is on a used cork sitting in a box/bag on the shelf. first thing that comes to mind is mold.

corks are cheap. why reuse em? I just got 50 for $7.00 at my lhbs. cost to me was so small i could not even imagine risking an infection to reuse an old one.

I'm not sure I understand the question. Don't your used corks have a hole in them from a corkscrew or opener? If not, if they are just opened corks and not used corks, they could be sanitized and ok. But all of my corks that have actually been used have a hole from the corkscrew.

You reuse for things other than wine making,

There are things in the environment that "feed" on wine. Acetobactor lives by eating alcohol; it's by-product of consumption is acetic acid (turning your wine into vinegar).

A used cork will have wine soaked into it. Acetobactor that is floating around in the atmosphere can come in contact with the wine soaked cork and set up shop. When it finishes consuming the wine there, it can "hole up" waiting for it's next opportunity. A fresh bottle of wine would be the GIFT OF A LIFETIME for these bacteria.

I wouldn't re-use corks unless I was making vinegar.