Regarding xylene -- before using any product of this type, please, please contact the manufacturer and get the Material Safety Data Sheet, or MSDS. (The store you buy xylene from is supposed to provide this for you, but often they don't.) This sheet can be understood by looking at the data sheet provided by Arts, Craft, and Theater Safety:
http://www.artscraftstheatersafety.org/datasheets.html
For legal reasons, they don't post data sheets online. So you have to request via email or snail mail. They will answer questions over the phone or via email -- FOR FREE!!!!!!
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Many of the best, most intricate carvers I know use the old pencil transfer method. Draw the most important lines on the *front* of you drawing, flip your drawing over, tape it to the carving material, and burnish the back of the paper with a pencil or spoon or burnishing tool. Voila! Your image is on the carving block, and no brain cells were harmed in the making of this project.
Lisascenic
who uses the pencil burnish method
owns her own respirator
and strives to use the least dangerous art materials possible