An easier, more convenient solution is just as close as the first aid department of you grocery store or pharmacy. 3M Nexcare Waterproof First Aid Tape. Cut 1/2 inch (or smaller) squares from this tape, and dot a few (I use about 8 for my 6 x 24 size ruler) about the ruler – about 1 inch from the edge. Provides just enough friction, removes cleanly. Lasts many months before replacing. A roll (about $5) lasts for YEARS. Leaves no residue. I’ve been using for years! I also add a fingertip size bit to my needle holding index finger, to help me keep a needle for hand sewing secure in my hands without joint stress… I’m sure they are other uses of this great product!