Dressed for the occasion, these cards are great for dealing to friends en masse. Write the greetings on glassine envelopes with a no-smudge marker, or print them according to the following directions.
There are 13 hearts in every deck of cards, so you may need multiple decks, depending on the desired number of valentines. Test the first round of printed envelopes before proceeding; in some cases, smudging may occur. If it does, vellum envelopes might be a good alternative. Or try a laser printer if you used an ink-jet one before.
1. Using a word-processing program, type 4 messages; size each to fit onto a glassine envelope, and stagger them a few inches apart on the page. Print onto a sheet of 8 1/2-by-11-inch paper.
2. On the printout, center 1 envelope over each message. Using removable tape, affix the top and bottom edges of each envelope to printout.
3. Using the manual feed on your printer, insert envelope-taped printout, and reprint. Remove tape. Repeat steps 1 to 3 to make additional envelopes as needed.
4. Insert 1 playing card into each envelope, and seal with a heart sticker.