Hi,
I don't think you need to create a button to do so!
Excel already has a button to turn on/off the Filter, you can find it in the Sort & Filter group under the Data tab.
If you have some filters and you want to clear them all, you can go and click this button twice to turn the filters off and then turn it on, this is will clear them all.
Tip: the shortcut to this button is (Ctrl+Shift+L).
Hope that helps