How to remove Credit Card info on iOS 7
Step 1: Tap on the Settings icon from the Home Screen
Step 2: Tap on Safari
Step 3: Tap on Passwords & AutoFill
Step 4: Tap on Saved Credit Cards
Step 5: Tap on Edit in the top-right corner
Step 6: Tap on the Credit Card you wish to remove
Step 7: Tap on Delete in the top-left corner and confirm. You maybe prompted to enter your passcode if you have one set.
How to remove Credit Card info on OS X
Step 1: Open Safari
Step 2: Click Safari menu then click on Preferences...
Step 3: Navigate to the AutoFill tab
Step 4: Click on the Edit button next to Credit Cards.
Step 5: Click on a Credit Card and Click the Remove button
iCloud Keychain and AutoFill are meant to be secure features of iOS and OS X, but the above instruction should allow you to remove your Credit Card information.
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