That check you mailed? Be alert — it could get “washed” and cost you thousands.

To lower the risk of having your mailed check stolen and “washed,” deposit mail before the last pickup at blue mailboxes. (Getty file photo)

Even in this age of sophisticated online fraud, the old-fashioned kind, carried out on hard copy, is still alive and well.

Check-washing schemes are on the rise, officials say, and unsuspecting people are paying the price.