Special note for Nelson Bubble lamps: Always use cool burning bulbs in these hard to find babies!
Most furniture can be wiped with a simple orange oil polish to clear dust and grime. Again try to use the gentlest method first, a soft wash cloth and mild soap with warm water.
Do not use oils on furniture when the varnish is coming up, the exposed wood will stain to a darker shade than the parts retaining their varnish, giving it a mottled or bruised look. This can be especially true for Heywood-Wakefield pieces in Champagne or Wheat finishes.
Chrome can be cleaned really easily with 0000 grade steel wool and a paste made from Bar Keepers Friend mixed with warm water. This will remove most rust, once you're done cleaning it up, wipe it dry with a soft towel and go over the metal with a bit of Never Dull or a bit of furniture oil to keep the rust from coming back.
Fiberglass furniture can degrade really quickly outside in the sun and rain, for this reason we never recommend Herman Miller shell chairs or other period fiberglass chairs as lawn chairs. However, if you would like to leave your fiberglass furniture outside, protect it with a wax polish available at most boat/ski retailers. It'll help to extend the color and gloss on your fiberglass furniture.
Re-upholstery is ALWAYS an option! Keep in mind that almost Anything can be re-upholstered for less than what a comparable item would cost. Ask your vintage dealer who they use for re-upholstery. In Austin we like and use Ambrose Upholstery. Dennis Ambrose is a fellow collector of Mid Century and has a great eye for what looks 'right' when it comes to upholstery.
Consider plexiglass sheets for wooden furniture that will have glasses, bottles or potted plants placed on them. A thin sheet of clear plexiglass on a tabletop can save you the expense of restoring a great piece of furniture damaged by water exposure. Of course, a thin sheet of glass will also work -- it won't scratch as easily as plexiglass, but it'll will break a lot easier. Either will keep you from getting the nickname "Coaster Nazi"! ;o)
The popularity of lucite is on the rise again, familiarize yourself with the weight difference between cast lucite and new acrylic, acrylic is lighter in weight and is visually more "plasticy" in appearance. Never clean Lucite with windex or other ammonia based products! Over time, the ammonia will react with the lucite causing crackling or hazing, crackling and hazing cannot be polished out. Minor light scratches can be removed but deep gouges are more difficult and sometimes impossible to remove.