(This post also applies to Bancor/Status/EOS/QRL/DCorp and other custom tokens)
Today I bought some Numeraire (NMR) and QRL tokens in bittrex and transferred them to my ethereum address. To make sure that the transfer is successful, I went to the ethereum explorer https://etherscan.io and entered my address. I was hoping that they will show up in the token tracker field when clicked on "[View Token Balances & Value]". But to my surprise these tokens didn't show up there even after 30 mins.
When I clicked on "Token Transfers" tab, I saw that the tokens were transferred successfully. Now I started wondering why they are not shown in the "[View Token Balances & Value]".
I thought of checking it in https://myetherwallet.com. To my surprise, they didn't show up even there. Also, I didn't see these tokens in the "Amount to send" field's drop down. If they are not in that list, I cannot transfer these tokens back to the exchange if I want to trade them.
After spending some time, I see a button called "Add Custom Token". I thought that this might help. I clicked on it, and it asked for 3 fields:
Address
Token Symbol
Decimals
I was wondering what should I enter here? For sure, the address must not be my own address because if it is, then it doesn't have to ask me. I know token symbol though. And what should I enter for "Decimals"?
I then thought https://coinmarketcap.com might help me. I went to the website, searched for Numeraire and open its page. I see couple of links. "Website" and "Explorer". I see that the token symbols is "NMR". One is done. Two more to go.
I clicked on "Explorer". It launched etherscan.io website page for the Numeraire token. From the Misc section I found the values for the remaining two fields. Please see the below picture.
I entered all these three values in the "Add Custom Token" form and clicked "Save".
Now I can see my Numeraire balance and also can transfer the Numeraire tokens to any other address.
Hope this helps.