Mucilin, from Thames Fishing Tackle of England, has been the classic choice for fly line, leader, and fly dressing for a long time. This firm paste comes in a resealable plastic "tin" with an applicator pad. Solid Silicone line floatant.
Use the Mucilin (with Silicone added) that the English and other fly fishing purists have used for over 30 years. The Thames Fishing Tackle Company of Redditch, England puts their name on every container of this time tested mucilin fly floatant, cleaner and dressing for fly lines.