Cleaning your outdoor solar garden lights is a very simple process and can usually be accomplished in a very short time depending how many lights you have installed. You can roll around the yard with a bucket of warm soapy water and a wash cloth and take the lights apart one at a time to clean them, but I prefer to take mine inside to be washed in the sink with a sponge, some dish soap and warm water.
I keep a cotton swab or three handy in case there are nooks and crannies that need wiped out and always be on the lookout for tiny bugs and spiders which may have taken up residence inside your LED lights! You need to be careful to not submerge the electronics when washing these lights. The electronic part is where the tiny LED bulb protrudes from. If you do accidentally get the insides wet you should remove the batteries immediately and allow the unit to dry thoroughly before putting it back together. Gently blowing off with a hair dryer is a quick way of getting the light dry enough to put back into service.
After picking up all of my LED lights I make up a dilute soapy water solution using dish liquid and warm water, then I wet the sponge in the soapy water. Next I take the light cover off and clean the stem and the plastic or glass pieces by wiping and scrubbing away the dirt and grime. I dip and rinse the sponge in the soapy water once in a while and rub all the parts that are not going to be ruined if they get wet.
These lights are typically made from high impact ABS plastic and anodized aluminum pieces which are both easily cleaned with a dilute soap solution. The hollow stems may need washed out using a garden hose followed by a thin bottle brush to clear out any dirt or bugs that may have accumulated. These lights can last many years with regular cleanings in the spring. I usually check the terminals where the batteries are inserted for any signs of corrosion and if this is happening I use the cotton swabs dipped into the soap solution to remove any loose crusty contaminants that are causing the corrosion. Replacing the rechargeable batteries is a lot cheaper than replacing the entire light and i would prefer to do this occasionally.
Most of the LED garden lights that I own take two AA batteries and you cannot just replace these with regular batteries since they could explode when the solar charging circuit is active. Cleaning off the solar cell is important even in between cleanings and this can help improve the performance of your solar powered lights dramatically.
Once you have all the parts cleaned you need to reassemble the LED garden lights taking care to make sure any rubber seals are put back into place the way they were before you started cleaning the lights. Test each one by covering the small photocell which looks like a tiny circle with a squiggly line inside it for a few seconds which should illuminate the LED bulb in your garden light. This photocell is usually on the top face of the light somewhere. Next put the lights back into their original locations unless someone you live with has decided that since they are out you may as well go ahead and do that honey do improvement list before you put the lights into their new locations.
Once they are back in place let them charge up for a day or two and then check them at night to see if all of them are still working properly.