Wrong-sized washer stuck to ARP head stud...

I ran into a rather unique and somewhat disturbing situation. I have the engine on a stand and I'm pulling it apart for a rebuild and pulled the valve covers off. Well, I have ARP head studs and somehow, instead of the supplied washer, a different sized washer got placed on one of my studs and it's stuck. I have no idea how it even fit on there, but the nut was torqued down and the washer (stuck to the stud) was about 1/8" from touching the head, so I know it didn't seal well before. The only problem is that I'm not real sure how to get it off of the stud now. I don't know where to get ONE replacement ARP stud, so I don't want to tear this one up, but I kinda need that washer off.

I did the install last time and have NO IDEA how this happened!

I was thinking about maybe trying to grind it down and hopefully it would break off.

here is a pic:

Thanks jrichker, but I have ARP head studs and they don't appear to have the reliefs that you speak of.

I used a grinder and ground that washer down and was able to pull it off. Ran a die down the threads to clean them out and good as new...except for the small knick I made on the stud w/ the grinder...oops; it shouldn't matter, though.

Thanks for all of the help:SNSign:

I forgot to ask before:

As far as I understand, the washers w/ the ARP head studs are hardened (obviously I'm short one now), so can I just get a hardened washer at the hardware store? I want to try to put the correct washer on there.