What can I charge for tenant overstaying 30 day notice.

[Bakhodir Ismatov]

I had a situation where the month-to-month tenant took additional 10 days to move out after giving me 30 day notice. Usually I just prorate 10 days of rent and move on. 

I am just curious what can I charge legally in this situation.

Can I charge another month rent?

Can I consider the day they moved out as a new 30 day notice start since they did not follow through with the original one and charge accordingly? 

I saw some sample leases that charge $100 per day for overstaying. Is it legal even if it exceeds the prorated rent?

Thanks