Preparing new concrete for epoxy

[600SL]

I have a new concrete slab about 6 months old now with a heavy coating of construction red clay on it. What is the best way to clean the clay prior to grinding. I don't just want to grind over it first without cleaning. I do have a pressure washer?

Also has anyone used the Dynabrush wheels available from HD. Last time I did this job I had to rent a grinder from United rentals for about $150 and purchase diamond insert for it for about another $250. Of course I was grinding an old Epoxy floor off with that. This time I only plan to clean and grind a new concrete floor. If I can get away with the Dynabrush that would save a small fortune.

 

[Gozo]

I used the Dymabrush and floor machine from HD and worked well. The floor was old and painted. Used the 100% epoxy solids with a primer about 6 months ago and its still adhered perfectly. I have a thread with pictures earlier on this forum.