If you are experiencing issues with your Chromebook performing slowly, you can delete the contents of your Downloads folder.
First, if you want to save important files in your "Downloads" folder, you should always copy them from your local Downloads folder to Google Drive. Any file in your "Downloads" folder is only stored locally on your Chromebook unless you copy it to your Google Drive. The procedure below will delete ALL the files in your "Downloads" folder, and they will not be recoverable.
Open your “Files” App
In the “Files” App, select the kebab menu ( three vertical dots ) in the upper right corner, then select “Select All.” You can also use the key commands <Ctrl> <A> to select all the files in your “Downloads” folder.
With all the files in your “Downloads” folder selected, select the kebab menu ( three vertical dots ) in the upper right corner, then select “Move to trash.” You can also use the key command <Alt> <Backspace>.
This might take a few minutes to complete depending on the number of selected files. You will know it is complete when you no longer see files in the “Downloads” folder.
Once all the files have moved to the “Trash,” select “Trash” from the right menu, then select “Empty trash now” to delete the files.
You will receive a warning that you will “Permanently delete these files.” Select “Delete forever” to permanently delete the files.
Again, emptying the trash may take time, depending on the number of files.