living room slide grease?

Its been a long time since I have posted. We are having month-long trip to Maine from Florida (where we live now) in our 2004 2720 SL and are on the road right now using WiFi, in South Carolina.

Our living room slide is getting pretty hard to pull forward. Is there anything we can put on the metal tracks or somewhere underneath that would lubricate it and make it easier to move? We are leery of grease for the mess and not fond of petroleum based products that make strong fumes.

I hope one of the many "TM Gurus" has an idea to share. Thanks!!
smookie