Ok guys, my grandpa used to be a magician, he started when he was five, and stayed in it till the day that he passed away at 87 years old.

Well I was going through all of the tricks that he had, wow he had tons of stuff. Boxes and trunks full, well I found an odd glass and I have no clue what it is for, it looks like a normal drinking glass except that it has a some sort of slot at the bottom, that goes nearly half way around. if you know what it is, do they make it anymore and what is it to be used for?

Without seeing it and based on your description, it is most probably a glass made for a Misers Dream routine. Coins tossed in can be easily retrieved via the slot. Thus a few coins will appear to be many dozen and even be made to vanish at the end of the effect.

On version of the glass had a small well built into the bottom as well as the slot in the side. The well held a few coins so that the whole Misers Dream routine could be self-contained.

I also think that is what it is. I have the
Abbotts trick like this. It is very good. I
would look around in the trunk for some old
production coins. These are getting hard to find!

The glass was marketed by Abbotts as a coin through glass. A silk was placed in the glass so it formed a pocket in the center of it. A half dollare was dropped into the silk. Because the silk covered a little below the glass it was an easy matter to get the coin and silk potruding out the slot. Magician grabs the coin and silk and pulls. It really looks like the coin and silk penetrated through the bottom of the glass. You could then pour liquid in the glass and drink it, third finger covers the slot, to prove the glass is solid!

I've also seen this same idea used with both a coin and a ball placed in the silk inside the glass. The silk and coin penetrate, leaving the ball in the glass. This can be done as a magician's choice ("Name either the coin of the ball.")

I believe the ball remaining in the glass gave proof to a "solid" glass.