Bon Ami does work and has been used as far back as I can remember

It was almost standard practice on early farm tractors with diesel engines
Of course this assumes that you have a good wall and rings and just need to seat the rings

Put it in a salt/pepper shaker so you can tap a llittle at a time into the intake air stream---varies as to how much or for how long----

Bon Ami polishes surfaces, its not abrasive and it probably wouldn't hurt the bearings if it did get there