Rent storage space.
This goes along with your basic de-cluttering tips. Get that junk out of and away from your house, period! The best part is, there are companies that practically make this easy now. You pack the boxes, they bring the giant storage locker right to your house, you load it, they come and take it away and store it for you, and when you move they deliver it to your new place. After all, you’re going to have to pack all that anyway when you move why not do it now, so you can sell your home faster and for more money?
And before you even ask, NO you are not allowed to leave the storage locker in the street in front of your house while your home is on the market!
Here are some addresses of storage services for you to research (note that I’ve never personally used these companies so I can’t attest to their reliability):
http://www.pods.com/
http://www.boxcart.com/
http://www.pspickup.com/
