You can exclude Microsoft Office autosave files by adding a wildcard exclusion flag specifically targeting them. Since Office's autosave files always have the same prefix, "~$", you can use this as your wildcard exclusion flag. That flag has the following syntax:
*\~$*
This wildcard exclusion flag specifically targets files or folders with "~$" at the beginning of their name. If you do not know how to add a wildcard exclusion flag, please see this article.