As an after thought......

If you meant an engine coolant flush.

Years ago I was instructed to flush a cooling sys with the following method.. I don't know if its a common practise but it was novel to me!
BTW was'nt on MB.

Flush cooling sys back to clean water. Include the block too.

Add a couple of handfulls of Laundry detergent.

Yes Laundry detergent........Seems that that fresh Lemon fragance will work in your engines washing machine!!!!

I suppose that if it is flushed clean after the soap it might be OK...I remember a rusty foam colour runoff. And, After the first flush too

Legal Stuff......
Best flush is to change the coolant every 2 years.