What about an anchor or two small golf clubs crossed

does he have a special hobby or sport? or perhaps a tribal or tattoo like design? or perhaps a ornament design perhaps of this site:

Ruth, I was thinking of a fishing rod and a worm! he he he!

If a design doesn't work then the other thing I would do is undo the two sides and unpick the stitching line and re-position the fabric by putting the part with the rust on it at the back and sew a fine edging on the front. I hope you can understand what I mean. Love Chris

Gerry has posted a free design at John Deer's site. It's an anchor and rope and I see Carol has suggested that. Love Chris

I have used a small star to cover holes. Where is the stain located on the shirt? That would help determine the type of design that would be the least noticeable. Hugs. Nan W

If you really think it's rust, your dry cleaner should have a product, think it's called Rust-Out, that will deal with it easily.

Have you already washed and dried this in a dryer? It might be set in if you have. Hydrogen Peroxide is a mild bleaching agent, you might try using it alone or mixing with Cream of Tartar; make a paste, apply, rub around and let sit for a bit. It's worked for me, might have to reapply applications. You could always try getting it out, if this fails unstitch the pocket and wash the creases out with vinegar to get a flat piece of fabric, turn inside out, refold and stitch the pocket back on.

Just have to add my recommendations - solution of salt and lemon juice and setting it in the sun to remove. My go to favorite is a product called ZUD. Here in California I have found it in the grocery store and hardware stores. Depending upon where you live you may have difficulty finding it. Good luck.

If the pocket isn't needed, take it off if the rust doesn't come out. No one but you and Hubby would know that it was ever there.