Black Flocking Adhesive Tape 3in x 30ft Projection Screen Felt Tape Border Ultra High Contrast Deep Black Felt Strips for Projector Screen Frame DIY

Of course, this is the tape that I use, it completely cancels out any light bleed. I placed the tape so that it tucks behind the screen by about 3/4 of an inch. I'd also recommend doing this with two people and using a laser level, because trying to lay the tape down perfectly straight with the screen is more difficult than you'd think.