It is often available at Lowes for $7.98 per quart (suggest purchasing two quarts and trying for yourself - to ensure your success and ONLY try on non-production items at first, we started with a "purge block" and then tried on real fine printed models before production items).
The best place we found for "bulk pricing" was:
http://www.essentialhardware.com/lampli ... 47187.html
12 quarts for $54.72 = $18.24 per gallon.
So try it out and post results here... Share what other tips and tricks you have.