Any uses for these small cards?

This is a cute box set with notecards.  However, after I made these I realized you can't find 4" envelopes anywhere and they are not accepted by the USPS.

 Box of Note Cards.

To make box. Take 6 x 11 piece of cardstock and with short side at top of score board score down at the 1 “ and 5” lines Turn so the 11 side is on top and score down on 1”, 5”, 6” and 10”.

On the 11” side cut up 1” on the fold lines (to the other fold line). Turn over and cut on the other 11” side. At this point you can cut a hole in the lid, add acetate and decorate. Glue or staple the tabs to the inside of the box. This is a 4” box.

To make cards. Cut 3 7/8 x 7 ¾ and score at 3 7/8. For the white front cut at 3 5/8 x 3 5/8. Mask with painter tape ½ inch all around the white card. Emboss a background with white and scrub different colored inks over the top. Stamp a design if desired and remove tape.

For a larger box for A2 cards...make a two piece box using

6 ½ x 8 inches and scoring at 1 and 5 1/2 on short side at top,

turn and score at 1 and 7. tuck tabs to inside. This will make a 4 ½ x 6 box interior.

To make one piece make one of the pieces an inch longer with an extra inch score to overlap.