Some shops can do them while still on the car. They will just disconnect the fuel line, disable the pump and then run a cleaning solution through using air pressure. Takes 15 minutes.
If you're gonna take them off you can get DIY kits really cheap to clean them. Essentially just plug the injector into a power source with a switch and then spray carb cleaner through while pressing the button. There on amazon for less than 20 bucks.
You'd have to dump in a crapload of rubbing alcohol to make any difference in really cleaning the injectors. It was a good old school trick to clear water from the tank and fuel lines but modern fuel already contains 10% ethanol alcohol (way more than a bottle of isopropyl alcohol) which does the same thing.
Yes ethanol holds water, so does isopropyl. Which is why its sold as "gas line antifreeze and water remover" aka "heet".
Alcohol binds with water (any type of alcohol. Methanol, ethanol, isopropyl) gasoline does not. So if there is water in your tank and you run 100% gasoline the water will settle to the bottom causing the fuel pump to suck pure water, or worse freeze (which is very bad lol). When alcohol binds with water in the tank it then allows it to mix with the fuel and be burnt harmlessly. Unless your buying marine or aviation fuel, your gas has 10% ethanol in it.
Rebuild your injectors. Purchase a kit at NAPA. Basically you are replacing the O rings and the mesh cage that is inside the injector. Not expensive and works wonders. There are a few You Tube how-to vids to help.