To disconnect your Facebook acccount from eHow, visit https://www.facebook.com/settings?tab=applications while logged in to Facebook.
Look in the “Apps you use” section for “eHow” (you may need to click “Show All Apps”). Click the “Edit” link associated with eHow then click the “Remove app” link that appears near the bottom of the newly revealed app information.
Confirm removal of the eHow app, and your Facebook account will be disconnected from eHow. You will no not be able to comment or log in to eHow unless you reconnect Facebook to eHow.