To get rid of the varnish smell, create a sponge from bread and vinegar, placing it in the room where the varnish smell exists. Varnish is a strong smell, so something equally strong that is known to eliminate the odor is required, such as vinegar.
In order to create the sponge from bread and vinegar, place a couple slices of soft bread into a bowl. Add 1-2 cups of vinegar to the bowl, coating the bread completely. Once the bread is saturated and becomes a sponge, put it in a location where children and pets cannot access it. Leave it in the room until the only smell is vinegar instead of the varnish odor. Typically it takes several hours for the varnish odor to disappear completely.