I have a set of OWS Iridiums... car missed with them.
Replaced with coppers @ 0.8 and hey presto, no missing.
In answer to your question of 'cleaning', I don't think that it is such a great idea. See the washers that compress slightly when you install new plugs deform slightly over time, but provide a compressive seal. If you remove and replace the plugs continually, this compressive seal can be not as good - once or twice should be OK though
That's what I think, anyway
PS if you have to take them out to clean every 6 months, that defeats the purpose of 'long life' plugs... and even then it takes 10 mins to take out the plugs
PS(2) you can buy my OWS iridiums off me if you want were in the car for literally 2 weeks