I have 120 "Multy" "Envirotiles" (made from recycled rubber tires) on my outdoor concrete patio slab.

Over the years, dirt, debris, muck, leaves, etc have accumulated under the tiles.

I'm going to pull up the tiles, power-wash the concrete slab, clean the tiles and lay the tiles back down.

• What is the best way to clean the tiles?
• What detergent should I use?
• What strength should the solution be (i.e., x part detergent to x parts of water)?