I am looking to having the tenant in the other unit of my live in duplex make a payment to me via mail box. Can I require Check or Money order only? Inglewood California

This is normally stipulated in a lease under forms of acceptable payment.  Common options are cash, personal check, money order, online payment, etc. Does your current lease have this section? 

The lease has no restriction on payment. Currently month to month. Obviously I don't want the rent in cash in a mail box. So is it legal in CA to restrict payment to Check or Cash?