How do I delete cache and other browsing data on my Acer Chromebook?
You have full control over your browsing data. This data includes your browsing and download history, cache, cookies, passwords, and saved form data. Use the "Clear browsing data" dialog to delete all your data or just a portion of your data, collected during a specific period of time.
For information on deleting all your data or specific items from your browsing data, visit Google's Delete cache and other browsing data page.
For more information, visit the Chrome OS Help Center.