SWEET OIL • FREE TRANSLATOR.ORG • Definition of Sweet oil

... very clever operations are performed. To restore a binding, paste is rubbed over the leather, and, after it is dry, it is washed over with a thin solution of glue size. Again, when dry, the volume is varnished and afterwards rubbed over with a cloth upon which a few drops of sweet oil have been dropped. Here is one operation just in outline. There are very many others, which I can only refer to. If there are ink marks on any of the volumes of your Clarissa, which you wish removed, this can probably be done so that no trace is ...

— The Private Library - What We Do Know, What We Don't Know, What We Ought to Know - About Our Books • Arthur L. Humphreys