I most certainly do vacuum the layout Allan!
After every use I rub the rails with an old oily cloth, then go back over them with a clean/dry cloth. It`s a large old layout, but there`s not a single power tap or soldered joint anywhere - lay it properly , keep it clean & it will never let you down!
Once a week I also rub the plastic with a clean cloth.
Once a month the whole layout gets hoovered.
When it goes into winter hibernation I spray all the track with WD40 for added protection.
I maintain my Jouef layout in the same way....our lass reckons I`m a right tart!
By the way, Autoglym works great on most old slots. But be very careful on early tampo printed cars & ones with a metallic finish. You only need a tiny amount to do a whole car.
Old plated Jouef cars come up amazing with Autoglym.