If you go to the craigslist main page for your city, you will find a whole section labeled "For Sale." Under that section, listed in alphabetical are different types of items to sell, and there is a section for appliances (I think it might be the first one listed under the "For Sale" category, in fact). Anyone looking to buy used appliances on craigslist would likely go there to find them. Even if they didn't, if they are looking for the kind of item you put up for sale they only have to enter the type of appliance and it should pop up when they search the site.

Of course, it is very important to protect yourself when you sell on the craigslist site. Only ever accept cash for your items, and meet in person when you can. That way nothing funny can happen.

If you want more assurance on your end, ebay is always a great place to sell anything, and you have a better system to back up the purchase of your item. Also, you can reach a wider range of people that way; people usually only use craigslist to find things that are close to them, whereas ebay is easy to use across the country,

There is an appliance section for sale on Craig’s List. This is the first listing on the “for sale” section. You can easily scroll through the listings there and find what you need.
Don’t overlook the free section listing. There are often appliances that people simply need to give away to clear out the basement or a storeroom. They may have purchased a new model and just need the old one removed. You can get some great deals that way.
Look at the listings carefully. There are many unscrupulous individuals that use Craig’s List. Some of the listings are fake and try to get you to purchase other items. Do not go to look at the product at the person’s home. Some items require that you do so, but check out the person carefully before visiting their place. You might also want to go to their location with another person.