Programs like 1Password let you store your secure passwords in a database protected by a master password. But how do you get those passwords into Safari? Generally, with copy and paste.

The problem is: any application can glance at your clipboard without your knowledge. While that isn't so bad if it contains a URL, you'd be pretty freaked out if it saw your Gmail password or your credit card number.

Single-Use Clipboard wipes your clipboard after you paste to ensure other apps can't grab its contents.

This extension works with most text fields and views on the OS, though some special cases may have to be patched in on a case-by-case basis.