How you clean your carburetor will depend a lot on what condition your carburetor is in.
A carburetor that has been running on your car without sitting around much will be cleaned much differently than a carburetor that has been sitting for 5 years or more.
If your carburetor has corrosion on the bottom of the bowl, then throw the carburetor away. There will also be corrosion in the passages that you cannot get out.
We at Mike's Carburetor Parts use an ultrasonic cleaner with Pro 300 as a mix, but the average person will not have access to this. Our professional cleaner had a cost of around $2,000. The cleaner Pro 300 is bought by the case for over $100.00. Some have bought one from Harbor Freight. Don't have any idea if they work as it is something I wouldn't buy, but if you do use Simple Green as the cleaner.
Take your carburetor apart. Unless there is a lot of dirt and corrosion around the choke valve and the throttle valve, I wouldn't take your carburetor down that far. It's too easy to break the screws. If you do need to remove the choke and throttle screws, grind the threaded end with a Dremmel tool until you get flush with the shaft. Carefully remove the screw with a screwdriver. If the screw stops, turn it back in and try again.
Don't forget to take a lot of digital pictures of your carburetor. Especially the rods and linkage. There will almost always be questions about how things go when putting your carburetor back together.
We recommend this cleaning brust set to help remove ethanol deposits in all the small tubes and passageways. You can order a set here.
Industrial cleaner & degreaser. This product worked very well. As you will see in the video, I immersed 1/2 of a very dirty carburetor and let it soak over night. Be careful with aluminum parts as they will discolor if you soak them too long. The test carburetor came out clean and free of oil & grease. Scrubbing the parts with a brush would have helped also. Cost for this product was about 11.00. This cleaner was used full strength. Directions say to mix 1 part Simple Green to 10 parts of water. Experiment with different mixtures. I would take a look at any aluminum or brass every 2 hours to make sure they are not getting damaged.
Some locations sell Simple Green Aviation which has been found to not discolor the carb bodies.
Soak all your pieces (except rubber) for 4 hours. We tested all of these and 4 hours seems to be about the best time regardless of what the instructions say.
For heavy deposits of grit and grime a toothbrush may be necessary to facilitate cleaning.
Be aware that leaving your parts soaking too long can discolor the metal, especially aluminum.
Wash all parts with hot water, being sure to remove all chemicals.
Blow out all passages with compressed air paying special attention to the smaller passages. Be sure air comes out of each end of any passage. Pay special attention to the very small holes, like the idle vent holes in the venturi cluster.