Roomster EGR

Anybody dismantled and cleaned the Ex Gas recirculation valve assembly on the 1.6 CR Tdi? I've had a replacement fitted but thought I'd have a go at the old one, as it is probably just gummed up. Should be a useful spare if it's successful. 

It's not just a traditional bolt on type, it's about 16" long and is plumbed into the engine cooling system when it's on the engine. It lives behind the DPF (Looking forward)at rear of the engine.