...
Select the encoding lists you want to block and click OK.
Mozilla Thunderbird
How to block a specific sender
Open an e-mail that you want to block the sender of.
Click on the menu button at the top right corner indicated by the 3 lines.
Then go to Message -> Create Filter From Message...
The sender of the e-mail should automatically appear in the area shown within the red box.
Also, you can choose to have the e-mail moved to the Junk folder or be deleted under the actions settings.
Blocking of character sets
Thunderbird has no option option to block specific character sets, however it does have adaptive junk mail settings which detects junk e-mail.
Under account settings, make sure to have Adaptive Junk Mail Controls enabled.
Once checked, Thunderbird will learn what e-mails are considered as junk by watching what e-mails you mark as junk.
