I have a wood plank floor that was “finished” at one time — ’bout 65 years ago.. Since then it has been covered with carpet and the finish is pretty much gone. There are no gaps/chips/rot… How can I redo these (with a light finish) on a budget? I think I’d have to sand them lightly —- thats all I know 
On 02.16.10, In Q&A, By Admin
Check this out:
http://www.ehow.com/how_1856_refinish-hardwood-floor.html
Call your local rental store and ask them about renting a sander, also ask them if they have a person on staff who is experienced at floor sanding. They will be able to give you some advice. You will probably needs to use 2 dif grades of sandpaper.
If your rental office can’t help you, call your local flooring store.
go to a hardware store and ask them about what you need… will need to know how big of room then buy the stuff a little at a time til you have it all and yes you will have to sand is best to rent a sander depending on how the finish looks now but its best anyways you have to break that seal to get the new to stick right.. can be done like over a couple weekends but dont start til you have it all ready to go it want hurt it to like sand one weekend and clean up then refinish the next will take a weekend to dry also so be prepared not to use that room
go to home improvment center or rental center you can rent a big sander for no more than 50 bucks a day. use a 80 grain sandpaper and run that over maybe twice. through some wood wax on there and your good to go. http://www.ehow.com/how_14590_apply-wax-wood.html
joannes link is pretty good but for a mirror finish lightly sand the polyurethane between coats.
both side?