As a Washington State resident your options are limited but not to the point where you can't do anything.
1) Go to Gemini
2) Create an account
3) Link your bank account
4) Hie thee to MyEtherWallet
5) Send Ether to yourself
6) Sell it on Gemini
7) Transfer the ca$$$$$$H MONEY to your bank account
8) Figure out if you owe capital gains since you had some money show up in a bank account
Almost nobody pays capital gains on cryptocurrency. If you go through an exchange that is regulated up the yinyang and into a bank account that is regulated up the yinyang, your likelihood of being the almost, rather than the nobody, increases.