You can throw a vacuum cleaner in the garbage.
Although it's best to recycle the vacuum cleaner or set it out for someone to pick up as scrap metal.
Vacuum cleaners contain copper wire and electric motors that also contain copper wire in some cases although some may be aluminum.
Copper is a valuable metal that will always be in demand and a person who goes around scrapping would quickly snatch up the vacuum cleaner if you have scrappers going around in your area.
I pick up vacuum cleaners and other things off the curbside for scrap including refrigerators, computers, lamps and, dryers, washing machines, computer monitors and just about anything else that contains some metal.
It all adds up and it's not my main source of income but I love doing it and recycling the metals and making some extra money.
In some places the trash is sorted before going to the landfill but some places the trash simply goes straight to the landfill.
Throwing a vacuum cleaner in the garbage is okay in most places but I would first set it out to see if someone wants to take it for scrap metal and if you have other scrap you can also list other scrap to take away for someone to come and get for free on Craigslist and it will likely be gone the same day.