This shouldn't be anything new to the DIY Cyclist/Mechanic and I really don't know why I didn't think about it sooner because I have used Beer Can shims numerous times on various seat posts.
You don't have to use a Beer Can, by the way, any aluminum can will work. I only like the Beer Can, especially a Pabst Blue Ribbon, because of the common association that beer has with cycling and PBR with fixed gears, but I don't where thick glasses and have a beard. Also, I have to thank Cliff, the cyclist who sent me some vintage handlebar bags, who suggested that I should do this.
Step 1, or Step 2 if you had to empty the can first, cut out a ribbon or strip of the can so that it's the width of the bar clamp and will wrap completely around the bars at least once and there is plenty of overlap. I use the the circumference of the entire can to ensure that I get enough overlap and then some.
Get on the bike and make sure the bars don't slip! If they do, you might have to add more can and also make sure the clamp it really tight!