I purchased LastTissue and really love it! I have a pack in my car and one in my nightstand. The silicone "box" feels great in your hand. It fits 5 reusable tissue/handkerchiefs. You take one out of the bottom slit, use it, and stuff it up top. When you come to the last tissue it has a special tag on it so you know to wash them.
I generally wash mine as they are used, but the design is very thoughtful. The tissues are not particularly soft - they are fine for every day use, but if I had a runny nose I would need something softer.
I bought several more for friends. I will purchase their full size kleenex replacement when our final box runs out.
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The only improvement I would suggest is changing the color on the special tag of the last clean tissue to something other than white. A white tag on a white tissue blends too well.