The name batik comes from the method (originally used in Java) of producing coloured designs on textiles by dyeing them, having first applied wax to the parts to be left undyed. This process can also be refered to as wax-resist dyeing.
I have been using only beeswax whereas many use a blend of beeswax and paraffin wax. Paraffin wax is fairly brittle and produces a lot of crackle. This crackle, either intentional or not, can be reduced by adding the much softer and more pliable beeswax.
There are a few methods for removing the wax after the dyeing process. Because of the nature of natural dyes, I avoid using hot water. I have been ironing out the wax. This is a traditional method of wax removal. The fabric is sandwiched between layers of absorbent paper and the heat is applied by iron to melt out the wax. It is difficult to remove 100% of the wax out and a residue is left behind.
I have found that the best results using natural dyes for batik are the dyes that can be used in a cold/warm dyebath. A hot dyebath would melt the wax on contact.
Natural clothing, bags and so on...