Hi, Merz

So, once you set the Subspool count to 0, SmarterMail will just continue to process any messages in any existing subspools. Once those are gone, you can just delete the subspool folders. 

I wouldn't manually move the messages - Just let SmarterMail handle it. That said, you could stop the SmarterMail service, move the EML and HDR files to the drop folder, then restart the service. (You'll still need to delete the subspool folders at some point, though. Or not.)