I don't know about Yahoo disposable addresses. Are they what some other mail providers call aliases? If they are, they will all use the same basic account settings -- the same servers in particular. You can manage them in Thunderbird using identities: https://support.mozilla.org/en-US/kb/using-identities http://kb.mozillazine.org/Mozilla_Suite_:_FAQs_:_Mail_Aliases If the server settings are different then you'd probably need to set up separate accounts in Thunderbird, but that's easily done.

Thank you.

This does appear to be the answer, even if it is not what I was hoping for :-)

The thought of manually adding several hundred addresses is daunting.

I very much appreciate that you took the time to respond to my question.

basically you may find they just do not work... Hotmail ones do not.