I used the saline in my blacktrack,.. just enough to wet the top few layers and now it is like new again,... and still retains the nearly waterproof final finish. I didnt want to use anything like the mixing mediums because I was worried about it changing that,.. and if you use the eyeliner mixing medium,.. I probably wouldnt line the water line with it. I have had my blacktrack since it was first released,... I use that one the most and it is nearly gone,.. all the rest of my fliudlines that I bought on exactly the same date,.. and don't use nearly so much,.. are still like brand new creaminess,.. I think it depends on how much you expose it to air and how much is left on how fast it dries out??? I like the little pots the fluidlines are in so much I am not sure if I'll want to B2M them??