DO NOT CLEAN IT! It’s beautiful and while it’s not particularly rare, you should consider putting it in a sleeve or coin capsule to keep it looking like it does today.
Something like this will do the trick: https://www.amazon.com/dp/B00LSZDK9O/ref=cm_sw_r_cp_api_glt_fabc_VBBE64461C84R59YVKX5
You can get coin capsules at any coin shop, amazon, or a lot of guys seem to like onfireguy capsules. They even have a few basic types at hobby lobby. Just make sure capsules fit the diameter for whatever coin you are buying.
https://www.amazon.com/Air-tite-Capsules-American-Krugerrands-Kangaroos/dp/B00LSZDK9O
If you are doing a 1oz, quite a few people have had success with Nationwide coin spot deal. Just avoid when they try to upsell you to other overpriced stuff.
You can check a few online prices and then call/shop around a couple local dealers to compare. I prefer buying local.