Crain’s Cleveland Business: Ohio-based RPM International Inc.’s Rust-Oleum business group has acquired Whink Products, an Eldora, Iowa-based maker of specialty cleaners. RPM said Whink is “the market share leader in the rust stain removal segment” of cleaners. Whink has annual sales of about $6 million, RPM also stated. Terms of the deal were not disclosed. Whink also makes specialty cleaning products for things such as carpet, laundry, cook tops, and drain and septic system treatments.