Engine flush... Yes or No???

I have had limited experience with engine flushes. As far as professionally, there was a "Bilstein " engine flush at the one dealer I worked at, and it was a chemical that was pumped through with a machine. The do it at home methods with the quart of kerosene etc. i would think there is a risk of clogging the oil pump pickup screen. If the engine is that sludged up, its time to come apart IMO. This is just my thoughts and I may be wrong.