With all the controversies surrounding Facebook, it is safe to say no one will blame you if you decide to stop Facebook apps from gaining your data.
To state the obvious the first thing to do is to remove the app from your Facebook account. One can do this either through the Facebook site or the app. Follow these five simple steps to remove an app from your Facebook account:
Step 1: Open your Facebook account.
Step 2: Click on the down arrow on the toolbar and tap on Settings.
Step 3: Select Apps and choose the apps you want to delete (for example Fashion World in the screenshot below).
Step 4: Click on the X icon that appears next to it.
Step 5: You will now see a popup which gives information about contacting the app to remove your data. Click on the Remove button on the popup.
Do keep in mind that just removing an app doesn’t mean that your data is also revoked from the developer’s database. To make sure that happens, one needs to contact the developer. Please note that this cannot be done through the app and needs to be done through the desktop site.