Most aluminum house siding is resistant to rust. Nevertheless, those ugly orange rust stains can still appear if your aluminum siding has been stained by some other metal object – a leaky faucet, drain pipe or perhaps spare building materials leaning against your home. Rust stains on your aluminum house siding can be a tough cleaning problem, but it is possible to remove them. The good news is you do not need to hire a professional. You can do the job yourself pretty easily.
First, you’ll need a few things: a garden hose (preferably with a spray nozzle), plenty of water, liquid dish soap, a bucket, a plastic scrub brush, cloth rags and rubber gloves. As a last resort, buy some CLR (calcium, lime and rust remover); just be aware that it is a hazardous substance which requires extreme caution. Once you gather the essential supplies, proceed to the following steps:
Step 1
Spray the rust stains with water from your hose. Use the highest water pressure possible. This will saturate the stains thoroughly and perhaps even eliminate some of them.
Step 2
Fill your bucket with water and squeeze out about a tablespoon of liquid dish soap. If necessary, use more soap and mix it into the water, stirring vigorously to create a lather. Wet your brush with the suds and start scrubbing the rust stains. Scrub with as much elbow grease as you can muster. Aluminum house siding is virtually indestructible, so go ahead and scrub those stains with gusto. If you begin to see improvement, spray the stains from time to time with the hose, which will clear off any rusty debris that you have displaced. If this step is working, keep doing it, since dish soap is relatively non-toxic. Surprisingly, liquid dish soap and water are sometimes enough to remove even the most difficult rust stains.
Step 3
If the above steps failed to remove all the rust stains, you must resort to using CLR, which stands for Calcium, Lime and Rust Remover. CLR is available at almost all hardware and home improvement stores. It is a toxic product, unfortunately, so use with extreme care. Use rubber gloves to protect your skin. Do not smoke cigarettes while using the product! Make sure your work area is well-ventilated, since there will be fumes, even outdoors. Saturate the rust stains with CLR using a cloth rag. Do not scour or scrub, just simply leave it there on the stains for a couple of minutes. Rinse off the rust stains with water. CLR may damage painted surfaces, including your aluminum house siding, so let this product be your last option.