This is from 2017
Berryman B-12 CHEMTOOL FUEL SYSTEM CLEANER (part
#0116) is extremely effective in the crankcase for the removal of gum, sludge, and other deposits IMMEDIATELY before an oil change. Because of the amount of cleaning that the product can do, it is not recommended to add it and then drive normally. This is due to the possibility of overloading the oil with deposits. This is not really a concern while idling and letting the oil temperature come up, but excessive deposits could be problematic once load is put on the engine.
If you would like to try B-12 as an engine flush, simply pour into your cold crankcase approximately 1½-2 oz. of
#0116 per quart of oil capacity. For instance, if your vehicle holds 6 quarts of oil, then you would use 9-12 oz. of or about two-thirds to three-quarters of one can. After you’ve added it to your cold oil, start the car and run it at idle 10-15 minutes until the oil is warmed up. Then change the spent oil and replace the oil filter.