What does this sentence mean?

In the sentence, "bilin'" is a rural, colloquial pronuciation of boiling, as applied in the homemade soap rendering process.

If you had given the context it might be answerable. "Bilin'" seems to be some kind of dialect, maybe Irish, for "boiling" so maybe they were indeed boiling soap, or maybe that was dialect for soup. Certainly nothing in the sentence suggests soap opera.

In my opinion, that collection of words is meaningless.
The apostrophe in "bilin' " shows a letter has been omitted but it is not a real word and would not become a real word if a letter were to be added.
The soap MIGHT refer to soap opera or to normal soap or to any of the chemical mixtures used in industry and referred to as soap. The context of the sentence might give it meaning but, otherwise, it is meaningless.