I ordered a 9.5mm IR cut (not IR pass!) filter from an ebay seller. It was $7, shipped, for a pair. Direct from China, of course.
Step 1: Testing the filter
I also made sure that it didn't matter which side up the filter was pointing. One side of the filter had a shiny coating. Both seemed equally good at blocking the TV remote's infrared LED. But just to be safe, I was going to use the shiny side on the laser pointer side (because one normally puts the shiny side of a filter on the side of the source).
Step 2: Glue filter on
Once the glue set a little, I put a bead of glue around the edge. And then eventually I put duct tape around the filter, and to some degree on the front of it (except where it counts), to make sure the filter wouldn't come off too easily in my pocket.
Ideally, I'd have mounted the filter inside, but I couldn't get the tip off the laser (and hurt myself with the pliers while trying).
Step 3: Final testing
Ideally, I should have done a control test before sticking the filter on. But I didn't think of that.
No doubt, the laser IS STILL DANGEROUS! But it is a little bit less so. And that matters at star parties where there are children.