I purchased at ICO using
https://ico.adshares.net/app and MetaMask. I can see my ADS tokens when viewing the site, but not when looking at my MetaMask account. How can I send these tokens to another wallet / exchange?
You can add token to metamask. Just clikc "ADD TOKEN" and paste our contract address. You should see your balance.
Metamask does not have option to send tokens. Best way is to use
https://www.myetherwallet.com/#send-transaction with option "Metamask / Mist"