How to Clean Concrete
There are many different ways to clean concrete, but most agree that the best way is to use a power washer. Power-washing equipment can be rented for the day and is simple to use. If you plan you day correctly, you could also use the rented power washer to also clean down your siding. You could also split the expense with a neighbor and each use the power washer for half the day.
As for stains on your concrete, there are a few methods you can try (depending on the stain)…
Freshly spilled oil – Kitty litter is the tried and true method for a fresh oil spill. It’s always a good idea to keep some in the garage just in case.
Old oil spill – This one’s harder. There are a few products that work well on old oil stains. Gunk brand degreaser and Swab a driveway cleaner product made by Gunk. If these don’t work, try Castrol SuperClean. You should be able to find these at a hardware store or auto parts store.
Rust stains – Oxalic acid will remove rust stains from concrete.
Tire Marks – Tire marks are difficult to remove. If power washing does not do the job, go to an auto parts store and ask for some Brake Cleaner. Just spray it on and wait a few minutes, then wipe off.
Mildew Stains – First power wash the area then apply a bleach water solution with a ratio of 1:2.
If you don’t have access to a power washer and have just ordinary concrete dirt build up. I recommend using the bleach water solution with a ratio of 1:2. Just pore it onto the concrete and rub in with an old broom. When the sun hits your concrete, it will bleach white.
Whichever way you decide to go, please remember to wear proper safety equipment as many of the above chemicals are caustic.
Oh and don’t wear your good blue jeans as any of the above chemicals will damage the fabric.