[header] How to remove varnish [title] Create good ventilation. [step] Whether your sanding or using a chemical solvent, it's a good idea to have ventilation. Open windows and use fans to create cross-ventilation if you're inside. 
If you can, take the piece outside or in a well-ventilated area to work on it. [substeps] To create cross-ventilation, place one fan so it's blowing into the area, and one so it's blowing out a window.