What is the best way to clean bits that have a bit of dark burnt stains? Am soaking the bit in oven cleaner overnight.
What exactly do you mean by burn stains? Cleaning material build up depends on the material you were cutting. If the end mill is discoloring, then there is nothing you can do about that. It's running hot. The only thing you can do is use that as a learning lesson and increase your feed per tooth. This can be done by increasing feedrate, decreasing rpm, or decreasing flute count. If you try to physically remove material to clean it, you will more than likely destroy the coating or cutting edge.
50/50 mix of water and vinegar (you can throw in a little bicarbonate of Soda) is less toxic and will work if you soak it for a while and use an old toothbrush. It is not perfect, but it is less toxic and smelly. I use this on blades and bits. Does a good enough job for me
What happened was the mill got too deep into the wood and started burning. Was using a non caustic oven cleaner. : ) It removed the burnt bits.