+1 on the vapers surprise. Sometimes its due to plain lazy and sometimes its grabbing the wrong bottle to refill a tank but ive stumbled upon a few great combinations and more than a few combinations that made licking the bottom of my workboots sound like a good alternative to the taste in my mouth. If the flavors are close, let one run out and refill. If not replace the cotton. That is the main reason i went thr rebuildable route. A few cents worth of cotton instead a $2-$3 coil