I usually clean my flylines really good after 4-5 fishing trips( sometimes longer) unless I use it in a pond or lake. I strip off the line into a bucket of soapy water and pull it through a soft sponge. I rinse it again with clean water and then apply the Cortland line cleaner and conditioner while checking for bad nicks in the line. I wipe off excess when winding it back onto the reel. I will usually re-tie on a new nailknot for the leader attachment at this time. I carry in my vest or chestpack a Cortland Fly Line cleaner (with "Float-Cote") pad and will run about 30ft of line through it in between trips. There are probably some better products on the market now, but it has worked pretty well for me over the years.