Here are some good tips:
Let no box go unmarked!
Use masking tape, a label maker, or permanent-ink pens. I like to tape an index card to the outside of a container. Or, take snapshots of what's inside. - Heloise
My all-time favorite label technique for a plastic surface is to apply clear Scotch tape in the space I'd like a label, write on the tape with Sharpie marker, and when I change my mind, just pull it off.
What are you labeling this month? Let us know!
Please join in and tell us your own declutter strategies!