are made from. 
I can use this oil as a painting medium - which makes the paint more fluid but 
also slower drying - as well as for cleanup. Walnut oil is more expensive than 
vegetable oil, but I use so little of it - about a tablespoon or two per 
painting - that it hardly matters. You do have to be careful to buy walnut oil 
with no preservatives, which would function to retard the drying even further.</p>
<h2><a name="surfaces"></a>Surfaces</h2>
<p>There are basically three different types of sur