I use Lestoil or Pine-Soil. Lay the saw blade in the cover of a 5 gal. bkt to soak for a few minutes (~5), then a light brushing with an old tooth brush under hot water does a great job.
Also from a friend of mine:
"I just read an article in a Woodsmith publication that rated saw blade and router bit cleaners. The blades had a pretty hefty build up of resin on the shoulders and gullets.
The results were in order....
Lestoil. It took only 5 minutes for 7 oz of Lestoil with no effort to completely clean the blade.
Extreme Simple Green. It took 15 minutes for 16oz. with no effort to clean the blade. (regular simple green attacks the carbide. do not use)
Rockler Cleaner. It took 10 minutes for 4oz. with littel effort to clean the blade
Baking Soda. It took 8 hours for 2oz. with little effort to clean the blade
Goof Off. It took 30 minutes for 3oz. Resin removed from flat surface but gullets didn't get clean.
CMT Blade and Bit Cleaner. It took 30 minutes for 3oz. Resin removed from flat surfaces but gullets wouldn't scrub clean.
They used a synthetic pad to clean the blades followed up with a brass brush if needed.
The Lestoil cleaned the blade in 5 minutes without scrubbing and it can be resued over and over again until it becomes cloudy. They recommend rinsing the blade in water then using a spray on rust inhibitor to prevent any corrosion from the water."