Box o' wine keeps varnish fresh and ready to pour

I never had luck keeping varnish fresh after opening the container. Then, over a glass of wine one evening, it occurred to me: Like wine, keeping air out of varnish keeps it fresh, so why not use the same method the wine packagers use? I removed the empty bag from inside the wine box, pulled out the valve, and cleaned the bag. After it dried, I poured in varnish, purged the trapped air, and returned the bag to the box. Now I dispense only as much fresh varnish as I need.
—Bob Slater, Ypsilanti, Mich.