Use of wood rosin
My son has a peanut and tree nut allergy. He will be playing the viola this fall. When reading, the information sheet I noted that the bow has to be rubbed with " wood rosin". When looking up rosin, I noted that Rosin," also called colophony or Greek pitch is a solid form of resin obtained from pines and some other plants, mostly conifers." Also, as "glycerol ester (E445) it can be used as an emulsifier in soft drinks.
Does anyone have experience with using these tree products? Thanks!!