If you have a premium line from the well known manufacturers you may not need lube juice at all like automotive stuff, kitchen products or even, gasp, line treatments made for fly lines by fly line manufacturers.
The slick coating of a good many modern lines goes all the way to the core. SA (3M) and Rio make line treating pads that remove a microscopic layer of coating and bring a fresh new finish to the surface. Being a dry surface it won't attract gunk and amplify the problem of getting your line dirty.
For real skanky lines mild bar soap (not detergent) then the pads mentioned above. For extremely funky lines all the above using the bar soap on a Magic Eraser and then your line treatment of choice.
For quick, on the water treatment the SA dressing works great. For a more durable and less wet yet VERY slick treatment it's hard to beat Rio Agent X or Glide. It does indeed take a bit more effort and time to do it right but it really works and lasts quite a while. What's that they say... "Good things take time?"
I have Zip Cast too but am less than impressed with it. It seems to come off as easily as it goes on and it cleans about the same as plain water in my tests. For all I know it could be just diluted Armorall rebottled. They are both water soluable from what I've witnessed.
I refuse to use anything on my fly lines that isn't made specifically for fly line material and the environment they're used in. I've yet to have a fly line develop surface cracks but have seen quite a few lines full of cracks on other folks reels.
If the cost of a real line dressing is an issue, you're probably in the wrong sport!
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