George Murphy (MBCA) sells in 35mm film containers for a couple of bucks. Don't have his phone handy, but it's in the Star magazine, or can be found in the archives of the Mercedes mailing list (http://www.mercedesmailinglist.com)

Being cheap & lazy, I used a water based, wax chain lube intended for my fleet of bicycles. It flows out nicely, dries to a solid, doesn't attract dirt & grime, etc. The sunroofs seem happy, so it works for me.