Ten years in a garage? That's a lot of car exhaust and carcinogens
on those rocks unless they were in rubbbermaid tubs tightly and thoroughly sealed with duct tape. If they were out in the open, or even in cardboard boxes, I wouldn't use it at all. No amount of scrubbing is going to remove ten years of who knows what got on those rocks if they were not properly protected from car exhaust.
On the other hand, if the rock was tightly sealed in plastic tubs, I would thoroughly clean the rock in tapwater. I would then recure the rock in tubs new tubs with heaters and powerheads, not in the display tank, with changewater and a generous amount of crud from an existing tank. Bacteria will be all over the crud which will seed the rock with bacteria. Once the rock is cured, I'd use it as base rock in a tank with rock already covered in coralline algae.
I'd also make sure reef chemistry is up to snuff by testing and adjusting alk, Ca and Mg every two weeks so coralline algae will spread. If you need links to reef chemistry links, let me know and I will post them.
But, imo, rock in a garage for ten years is a touch and go proposition.