I've been using these to hang lights in my Windows for a couple of years now.  The first year I left them on, all year.  Last year I removed them and saved the plastic clips in the hopes of buying refill adhesive this year and possibly one new package of clips.  Disappointed that you can't get refills.  Seems like a huge waste.  Wonder how many sea turtles these things kill....  I'll be finding a new method for the lights this year.