This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
The recommended clarifying mediums, except animal charcoal, can be used time and time again, if they are scalded and carefully washed with hot water after every operation, else organic matter would form which would be a source of contamination to. syrups passing later on. When these precautions are taken the first price of the clarifying materials need not be much considered, as they' can by proper care be employed for an indefinite time.
We may briefly state that glass-sand, powdered pumice-stone and asbestos, besides filtering-paper pulp, are the most suitable and effective clarifying agents both for plain and compound syrups, the fruit-acids being indifferent to them. Magnesia should be dispensed with, being too expensive and unfit for acidified and other syrups; "while animal charcoal and albumen should be employed only when ordinary sugar is used which requires refining. Never use animal charcoal to strain flavored syrups, as it will absorb the flavor.