I tend to avoid using hydrochloric acid on things electronic - as it's incredibly corrosive - unless you wash everything off and dry thoroughly. It's great for rejuvenating ironware such as files (full strength) or things like corroded battery contacts.- wash and oil immediately after. Just rejuvenated a collection of jeweller's files. Phosphoric acid is far less volatile so doesn't cause collateral damage- so more appropriate for electronic applications.
