It's probably some type of UUEncode or YENC stuff, but it could
certainly be any sort of file, like an EXE, a RAR,ZIP, etc. Try
searching for UUdecoders/Yenc utils, since I'd suspect it's probably
one of those. [There are several freeware apps to decode such files.]
Typically these come as attachments, esp if they're large. But they
can also be contained in the body of the email. UUDecode/Encode/Yenc is
often used with Usenet binaries readers, so check under that too, since
most good how-to sites on Usenet binaries will tell you how to decode
such stuff.
Usual tip-offs are text like "begin..." and "end" at begin/end of the
data. "Begin..." will typically be followed by the filename.extension
at/toward the end of that line, eg:
begin.........................myPicture.jpg
Depending on your system/email app, you may need either to copy/paste
the text out to eg a text editor, or save the email as a filetype your
decoder can recognize.
If this doesn't do it, check for a program called TRID
http://mark0.net/soft-trid-e.html
which is a file identifier.
Other than that, it could always be some sort of encrypted file.
