Fly lines need cleaning for several different reasons: use in saltwater, brackish water, and extended use in freshwater, particularly with lots of suspended solids or algae. You will find that a dirty line ceases to cast as far, is more difficult to pick off the water and sticks to rod line guides on the cast. It can stick to your hands as well, and if you are managing several loops of stripped-in line in your line hand, the bottom of the loops is in the water, and it will stick to that water, too. Clean your fly line more often if used in brackish water, the worst combination of fresh- and salt-water, typically in estuaries.
All ‘dirt’ problems lead to reduced casting distance; this can be as much as 20 feet, which for the average caster can be 33- to 50-% of casting distance. Dirty lines also take more oomph to cast all day, to compensate for their unwillingness to slickly rocket out to land within a foot of where you aim to cast the fly.
Always have a target in mind, and over the years, you will become amazingly accurate, even with other problems in your casting. Such accuracy is critical when aiming for a rising fish, and when you are laying a fly just off vegetation providing cover, typically on the far side of a river.
If your cast is a foot long, a tug of war ensues, with your fly getting broken off if it is stuck on vegetation. The most important thing to do in a long cast, is to yank the line back asap, before the fly has gotten settled in green or wound around twigs. But keep on trying, because you will never become accurate, unless you try to be accurate for a long time. Accept that you will lose a few flies – the price of becoming more accurate, and catching more fish.
Once a new line has worked through its best, new days – I don’t clean a line until it is through this early period – put the reel with its line in a bowl of warm water after every fish. Use a small amount of dish soap, water just covering the reel. Don’t use too much as soap can degrade the surface of our expensive fly lines. Leave the reel over night and the next day let it dry on a cloth towel, rather than a paper towel. Then wipe the reel with the towel.
Check your line for cracking, or patches where the coating has come away from the braided cord on the inside. If your line is cracked, chances are that it is sinking, even if it is a full float line, because it is full of water. Patches of missing coating are usually from fishing in weather below zero, and water forming ice on lines and guides. When the line gets stuck, a patch of ka-ching fly line breaks away, the beginning of the end for the fly line. Don’t just keep using it, as the ‘hinging’ of a patch of lower density line between two lengths of higher density line will ruin many casts, driving you bonkers. Any fly line surface cracked along its length should be replaced.
I would say that not buying new fly lines soon enough is the number one problem that fly anglers face with casting distance, regardless of level of acquired casting skill. As fly lines cost $50 - $100 each, replacing them hurts. On the other hand, not casting properly, getting the distance and accuracy that comes with casting practice, is a complete waste of your time.
So, replace fly lines sooner rather than later. And keep the old one for awhile. I have changed only to find that the new line caught fewer fish because the old, waterlogged line was putting the fly in the fish zone, while the new line put the fly above the fish zone. This happens more frequently in beach and estuary fishing for incoming salmon, in salt or brackish water.
Most fly lines come with a small bottle of fly line cleaner, or slick. These are applied after your gentle cleaning step. Cut a two-inch square of cloth fabric from an old shirt that has been put in the cleaning-use pile in your house. Pick something that won’t lose particles onto the line surface, the equivalent of putting dirt back on a cleaned line. Similarly, don’t use paper towel as these ‘bleed’ paper particles back onto the line as you draw it through.
Keep a poster rolled up for cleaning purpose, then roll it out, face down on the floor so that you aren’t stripping line onto a dirty floor. Saturate your square of fabric with cleaner/slick, then with the drag on your reel almost fully off (don’t fully eliminate it or the first time through, dragging line off the reel, you will end up with line over-runs on your reel, and having to sort that out with hands covered with slick ‘grease’), fold the fabric around the fly line, and strip it smoothly through, reel on a clean surface below.
Prior to using a fly line or after completely cleaning the line, mark the end of the ‘head’ on the line, where the thicker head ends in slimmer running line. Most manufacturers change colours between head and running line these days, so spotting the change is easier than in the olden days.
Take a black, or other contrasting colour, magic marker, and mark two inches of transition so that you will know the end of the head, something that comes in very handy when casting. You simply put the marked line within the top rod guides and the line will not hinge, resulting in longer, more accurate casts. Also, strip another 20 feet and mark that spot with magic marker as well. That is for the lengthy casters who want to reach fish that are further away. It also indicates proximity to the end of the fly line where it contacts the running line, something every fly fisher wants to know, as once that expensive line completely leaves the rod on a long run, we become worried of losing the fly line.
Returning to the cleaning stage, strip the line – head and twenty feet to the running-line mark – to one side of the clean poster paper. Saturate the fabric square once again, taking the fabric in your opposite hand, and strip the line back through the fabric, placing the pile on the other side of the poster paper. Change position of the fabric stripping point frequently, as you will find the gunk on the line gets stripped onto the fabric, and you want to present cleaner fabric to the fly line surface.
Finally, take the saturated fabric in your opposite hand, and bring the line through the line slick for a third time, making a pile on the side of the stripping hand. Go wash your sticky hands, let the line dry over night and put the fabric in the garbage. The reason for putting the pile on the stripping hand side is that with as much as 80 of line/leader stripped onto the poster, you can tangle line very easily if the next strip results in one pile mixing with the other pile.
The next day, with a new two-inch square of fabric, fold it over the line and strip the pile through, three times, each time making a pile on the opposite side of the poster. Frequently change the fabric square position so that fly line is moving through clean fabric. Once done, you will find that the fly line has picked up a lot of static stuck particles of gunk, and the fabric will have dirty streaks where fly line was pulled through it. Finally, the next time you are out fishing, revel in how well your line strips, casts and lifts from water’s grippy grip.