Venetian blind cleaning tool.
https://diqn32j8nouaz.cloudfront.net...r_fullsize.jpg
Previously:
https://www.homemadetools.net/forum/...953#post198779
https://www.homemadetools.net/forum/...295#post121722
https://www.homemadetools.net/forum/...001#post179822
https://www.homemadetools.net/forum/...369#post131305
https://www.homemadetools.net/forum/...001#post125290
