Magna Tank Gel Pens. Even though they're cheap and no longer available, I love them, because they are ergonomic perfection for me, and of course, they're...tanks. I reached for my next-to-last blue Magna Tank Gel pen, and noticed the endcap was loose. In fact, it threaded all the way out, exposing the open end of the ink tube. Easy access! That got me wondering whether anyone here has heard of, or developed, a homemade gel ink replacement. A quick innerwebz search didn't reveal much. If you can refill stamp pads and markers with homemade solutions, why can't you refill gel pens? Anyone have an answer? Thanks.