It has been suggested by someone who *knows*, that vinegar is a good
medium for clearing out persistant residue in a narrowboat toilet holding
tank.

Apparently you leave it in to soak for about 24 hours before
thoroughly flushing.


In the 16 years we have had our boat the pipes in our head has only cloged up
with salt and whatever once. After that we used vinegar in the pipes and
holding tank at least twice a year. No problems since, so I guess it works. We
also use it in the sink drains. I use it to clean the carbon off stove parts
and a lot of other things. It seems to be a good solvent.

I use it to clean the salt out of my outboard too.

Dick