I sometimes have business cards associated with hard copy paperwork for some clients. In those cases I put the main or cover document on the photocopier with the business card aligned just below it, then copy using a reduction to 93%. This marries the business card to the paperwork and THEN I pitch the card into the recycle bin.
For paper-based stuff, I've learned that reducing & combining pages often creates thinnner files and also puts more info at my disposal on a given piece of paper. Lots of times I'll even reduce two 8-1/2 x 11 sheets to half size on a single sheet. It's still readable.
Many years ago (before I started using my PalmPilot and the "enter the data and toss the card" process), I found a small paper punch in an office supply store. The punch was designed to make (in one press) the cuts necessary in the bottom of a business card for placing the card in a rolodex file. As I recall, the punch was kinda expensive (US$5 or US$6) for a device about 1 inch by 1 inch in size. But it certainly did the job.
In the spirit of purging things no longer needed, I may have finally thrown it away some time ago, when I went "electronic."
It's Labour Day weekend and I'm sitting in my office GTD-ing my files.
I find an old pile of business cards in a box of papers from my California office 2000-02, I check that they're all in my Outlook Contacts - they are - and then I toss them toward the business card file box, thinking, that'll be a little later in the GTD-ing of my main office.
Then I think: Wait! Should I keep the cards at all?
I check the DA forums, and find this thread, and the answer is: No!
I throw mine in my in basket at home. Then when I'm processing my in basket I enter them into the Palm Desktop, which enters them into the Palm on HotSync. Then I toss the cards in the wastebasket as part of my ongoing jihad against paper accumulation.
On GTD Fast, DA says he staples them to a letter sized sheet of paper, which gets filed according to the event on which they were collected. If a group of cards were collected at a particular conference, he creates of file for that conference, and all the cards are stapled to the paper, and the paper is dropped into the file.