For centuries the preferred waxes used in batik have been beeswax, vegetable and animal waxes, and more recently paraffin. While these mixtures can be boiled out of cotton, removal from acid-dyed silk requires dry cleaning, specifically the use of perchloroethylene, a toxic chemical which is heavily regulated by the EPA in the USA.  In the likely event that perc will be banned in the future, batik artists will either need to find another way to remove wax from silk or find an alternative resist.

Pic: Soy pastilles and soy slab with USA dollar coin

Artist Dorothy Bowen has been working with soy wax as an alternative resist on silk since 2002.  Advantages are that the fumes are not toxic, melting point is lower, and the wax can be washed out with warm water and synthrapol.  While soy wax shows promise as an alternative resist it is not generally recommended for immersion dyeing.  Dorothy Bowen has written a great paper exploring instances where artists can use soy wax for its unique qualities and thereby eliminate exposure to paraffin fumes and perchloroethylene.

You can read more about this subject and download the full paper on her site:

http://www.db-bowen.com/soywax/soywax.htm