Originally Posted by teammpp

I personally use massivemods way. I clean thoroughly with a small baby toothbrush (soft bristles) with either kerosine or if I dont have any then I use straight fuel. I dont like using air to clean out the motor. It always seems to blow the dirt into the bearings unnoticed. Instead try using 3in1 oil sprayed through a airgun. I prefer leaving the engine soaking in 3in1 oil or equivilent overnight (totally stripped down - put all the separate parts in). That helps dissolve/clear any missed particles trapped in the bearings etc...

I have heard of people using detergent. I havent personally used this but I do know from other applications that you should steer away from powder based detergents like washing powder. The granules act like sandpaper and will at worst leave deep gouges in the case. Use washing liquid if anything. Make sure to rinse well afterwards to get it all removed and then steep the engine in something like 3in1 oil to relubricate and dissolve any missed detergent etc....