hey guys kinda new here, i signed up because its a really good site for help and you guys are ususally on the ball.. anyways i recently ripped out the smog pump on my 90 GT and just recieved my thermactor plugs from summit today (for the check valves on the back on the cyl heads). when i ripped out the old pipes and tried to insert the plugs i noticed the holes are almost 100% clogged with carbon buildup. any ideas on how to clean them without taking off my heads?? sorry for the length and thanks in advance