How to clean gunk out of new build

I’ve run marvel mystery oil- 1 quart with rest 10w30 under a light load for 10mins and let sit over night. Then run again till hot and drain. Again light load if any.
Best you can do without taking apart and cleaning.:

Sea foam also makes a cleaner but I’ve yet to use it. Diesel or Kerosene has no lubrications and will kill the bearings.