This section is from the book "The Gardener's Monthly And Horticulturist V23", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
One of my customers having painted his hot water pipes with coal tar, with the usual result, was advised to take them out and burn them to take it off. The house was new and beautifully finished. The pipes, put together with a rust joint, which would have necessitated a great deal of tearing up and much labor to get them out. The proprietor preferred trying experiments first.
He washed them with strong hot lye, applied with a swab tied to the end of a stick. One man went first and swabbed the heaviest part off, and another followed whose lye did not get foul so soon. Two, or at most three applications, made them as clean as when first put in, and there was no trouble afterward. We tried benzine and several other things, that I do not now remember, without the desired effect.
[The most amazing thing about all this matter is, that there should be such a number who tar hot water pipes. It is only explicable on the theory that there is a fresh crop born every day. Those who have read horticultural papers surely do not do these funny things. - Ed. G. M.]