The fastest way I think would be to edit the "web.config" file. Usually you can find that file under: "C:\inetpub\wwwroot\wss\VirtualDirectories\YOURPORT".
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Open that file in Notepad and search for "blob". You will see this line:
Set the last parameter "enabled" to "false" to deactivate BLOB Cache. Set it on "true" to enable it.
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Also you can change which files should be part of the BLOB cache simply by changing the filetypes in the "path" parameter.
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I changed the "path" parameter after one of the CUs for SharePoint 2010 was throwing a lot of errors.