LP is for leather, don't use it on twill. I rewax my twill stuff once in a blue moon. It's a tedious and time consuming process that involves several cans of wax and a hair dryer. The process is very much like my infamous Crane's method of waterproofing boots. It doesn't darken the fabric anymore than what a "fresh" new bag from Filson looks like. In the last year I added a tan twill messenger bag and a tan oiled tin cloth backpack. My backpack is one of the early ones without the sleeve. It works great for rock hunting/fishing/hiking day trips. I don't find it to be too uncomfortable when it's loaded up. Sure it's not an Osprey but for light trips or around town it isn't a big deal IMO. The messenger makes for a decent camera bag and it's also great for the days that I don't need a 257's worth of crap with me when working.