I saw this and thought it might work for cleaning out the heat tubes under the intake manifolds. Snake Bit........flexible drill bit
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sure if they are flexible enough to turn the corners without drilling through the tubes.
I usually use an old clutch cable and a lot of time to rod out the carbon through both sides. TG I don't have to do it to too many Beetles anymore, but regrettably I don't see a lot of them anymore. :-(