Removing the border of image submit button

 I've put a clear form button at the top of the form, but I don't want the form to be submittable from there.  (This clear form button would be used if someone wanted to clear a previously submitted order or if they wanted to start over once they had started filling in a form.)   Since the clear form button only comes with the submit button, I have used a wee image that blends into the form for the submit button so it won't be noticed by a user.  Unfortunately, the image has a red border.  How can I remove that red border on this pseudo submit button?

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