What are some of the lesser known things Batman has "kept"?

he  keeps evertthing the giant penny, a joker joker card, a t rex, one off deathstrokes swords,  the vampire monks shroud, batgirl and robins  costumes, and also mr freezes gun. And many batmobiles.
oh aand kids

lol @ the kids
thought this thread would be a little more popular. Comic collectors talking about the one comicbook hero who collects stuff from his comicbook universe.

I believe Superman keeps "trophies" too.
 
BTW, whose weapon was the T-Rex?

depends, they rewrote a lot of the origins of the items

Billions of dollars... Not a lot of people know this but Batman is actually rich.. A multi-billionaire in fact... He's Bruce Wayne!!!! How crazy is that?!? hehehehe!

he has a copy of Alice in Wonder Land

" kryptonite, one of every color. oh and meow mix............its personal "

His stamp collection and all the state quarters.

"I think I have one of the issues of "secret origins and files" where they have like a tour of the Batcave. There are supposed to be like 7 levels or something and apparently one of them is very secret and only he knows what's in there... "
 
Thinks I assume are there:
 
- Catwoman's panties
- The truth about Joker's identity
- A direct live cam feed to Power Girl's shower room

" @Sydpart2: Theres actually  a more receent batcave map, published at the end of  the time and the batman trade  It details each of the various levels including the hall of  trophys and hall of armors along with the garage level, andmost other areas. It even has descriptions of sublevels 1-6  with sublevel 7 being  deescribed as only batman knows its purpose. "