Warning: Affiliation links ahead.
If you haven't been following along, a capsule wardrobe is a core set of clothes that you wear. These may shift depending on the season and if you have a separate set of clothing (like a uniform) for work. Once you've gone through your clothing and removed items that: 1) no longer fit 2) are in too poor a shape to repair 3) have too many "duplicates" like a lot of white blouses 4) or too many of for example several coats when maybe you live in Arizona and need only one heavy and one light. Then the real work begins.
You can go ahead and trash the clothing that is in too poor quality. You may be tempted to cut them up and use them as rags. And if that's okay then do so, but if you're like me and rags seem to accumulate, it may be best to dispose of the clothing altogether.
The rest you may say to yourself "well what do I do with them?" Sell them.
There are a number of used clothing stores in my area that I have sold clothing. There are also a number of online places that accept clothing. These can be divided into two categories: ones you list and ones that buy them and then resell them. You'll need to figure out what items they accept and how they wish the items to be shipped. For example: Thredup will send you a bag and they will accept wallets and handbags, clothing for women and children, and shoes. They are particular about which brands they will accept too. Whereas Swap will accept clothing for women, children, and now men, shoes, children's items, decor, movies, and books. You can send your items in a box but it must be a specific size. Double check return policies if the company elects to not sell your items. Some will donate the item for you or charge you shipping to return.
If you are looking to sell more directly, there is always Craig's List and Kijiji which do not cost you a fee. Ebay and Poshmark are also good but they too will charge a fee. Ebay will also accept some items and sell them on your behalf.
If all else fails, there are plenty of non-profit places that will accept quality donations.
I also suggest shopping at second hand places if you discover "holes" in your wardrobe. As one friend put it once, "I always seem to have way more tops than I need and not enough bottoms." Maybe this happened to you while you were weeding out your closet.
Make sure to look for what you want exactly or you could fall into the stuffing-your-closet-with-unused-clothing trap again. Also choose a quality article not a cheaply made fast fashion garment. Goodwill now has a online place where you can bid on quality items without having to sift through the store for a fraction of the cost.
Have a Happy Closet!