I want to clean my facebook wall but someone is continue posting some xxx pictures on my behalf. I could remove these but how can i stop doing further activities?
you should have allowed an app to post in your fb so it is posting it. The app name should be show as "via appname" beside the posts. You can go to https://www.facebook.com/settings?tab=applications Revert access to any app that seems suspicious or you are not using
Delete your posts and then change your password and don't tell anyone your password. I'm guessing that you have told your password to someone and they are using your account to post on your behalf.
look for your Facebook App And Disable Or Remove all The App You do not know And Change The Password Of your Account and Choose disconnect from every device =D