yEnc?

Usenet requires that a binary attachment is "encoded" before it is sent. A message with a binary attachment which is not encoded will be corrupted during transmission - or transmission will be denied. Typical encoding methods are  UUE and Base64.

Transport of messages by news was restricted to US-ASCII characters when the protocols were written (20 years ago). Those services were created to transport only plain US-text. Special characters (control-characters, symbols, non-US-characters) were forbidden. But, because people also wanted to send binary attachments, some 'tricks' were implemented: The binary was changed to US-ASCII-characters before transmission (encoding) - and back to binary after transmission (decoding). 

Unfortunately there is a price for this 'trick': Encoding makes a message longer. And not just a little, but 33%-40% longer than the original attachment. This results in 33%-40% more bytes for a message - 33%-40% more time for the transmission - 33-40% more disk space on the drive where there messages are stored.

yEnc saves disk space and transmission time by only adding a few percent to the original file. It promises to shave almost 40% off the file size as compared to traditional encoding.

Starting with version 7.5, Pluckit supports the yEnc format and automatically detects and decodes yEnc attachments.

Pluckit can handle singlepart yEnc, multipart yEnc, and even yEnc'ed RAR's.