I am considering mechanically cleaning my inlet valves in the head with the intake manifold off - any thoughts? guidance?

Story, my car had PCV issues (as in some other threads) which have now been solved with a proper filtered catch can in the PCV line. Unfortunately the inlet valves got quite gunked before I understood the problem but decided to leave as it was still running OK. Now I have an intake gasket failure so have the manifold off and can access the back of the valves. I was thinking of using a brass scraper to remove the worst of the gunk, with the valve closed!! and vacuum out, then finish with a spray valve cleaner once the engine is running again.

Comments?