I've been using the same 4 cartomizer(s) for about 2 weeks now and I switch off when I'm out of juice. I have a KR808D-1 model. Lately, it's getting harder to pull. When I take a drag I usually got to pull a lot harder than usual. I was wondering, is it the juice, maybe the wick that's making it hard? or should I just clean it? I plan on buying new cartos anyway, but as of now wanted an idea if there's anyway of saving the cartos or just toss them away?