Video shows old style tank, but what about newer style tanks with fuel pump inside tank and larger openings.  I assume I remove all parts from inside the tank before the 3 steps KBS Kleen, RustBlast, and Tank sealer, correct.

Suggestions for plugging such large openings?

Regarding pipe cleaners for plugging small openings

Do you mean that the tank sealer is so viscous or thick or has such surface tension or some other property that the pipe cleaners block the tank sealer from adhering to the inside of tubing which is sealed by inserting pipe cleansers long ways into the tubing, using as many as it takes to fill the opening on the inside or the tank prior to applying the sealer?  I see to wait until sealer is tacky and now longer dripping or running to remove the pipe cleaners, correct?

Yes, it is always best to remove all of the parts from the inside of the tank first.

You can plug the larger openings with heaving plastic and duct tape or corks work really well if you have corks large enough.

As far as pipe cleaners, you will want to get them in the tubes so the tubes are blocked. Once the Tank Sealer has tacked up some, pull the pipe cleaners out and the action of pulling them out will coat the inside of the tubes. This works really well.

Please let us know if that helps and if you have any additional questions.