Notice to quit(1) A tenancy may be terminated by notice in writing, served not less than the respective period fixed before the end of the applicable tenancy, as follows: (a) A tenancy for one year or longer, ninety-one days;(b) A tenancy of six months or longer but less than a year, twenty-eight days;(c) A tenancy of one month or longer but less than six months, twenty-one days;(d) A tenancy of one week or longer but less than one month, or a tenancy at will, three days;(e) A tenancy for less than one week, one day.(2) Such notice shall describe the property and the particular time when the tenancy will terminate and shall be signed by the landlord or tenant, the party giving such notice or his agent or attorney.(3) Any person in possession of real property with the assent of the owner is presumed to be a tenant at will until the contrary is shown.(4) No notice to quit shall be necessary from or to a tenant whose term is, by agreement, to end at a time certain.(5) Except as otherwise provided in section 38-33-112, C.R.S., the provisions of subsections (1) and (4) of this section shall not apply to the termination of a residential tenancy during the ninety-day period provided for in said section.Based on this, it looks like for month to month occupants, 21 day notice is the appropriate time for Colorado, but I wasn't sure if there was any specific code that needed to be followed in Arvada aside from the Colorado text above.  

Information is Power – get as much as you can.Ask questions, what is the reserve (sometimes they will tell you, sometimes they won't, what is the balance of the mortgage, if you are the high bidder will you get the property free and clear of any liens – can you have immediately possession?

Then you can take possession of the property once all the redemption rules are met.  

Let me clarify...I assume the home is still in the foreclosure process since the bank has not taken possession of it yet or listed it with a realtor.  

I believe your marketing must reflect how the specialized knowledge that you possess can/will solve your prospects problem(s), primarily through using your expertise to build trust. 

We also have occupants sign an agreement saying they are giving up possession and all rights to the property in exchange for the cash for keys.

It can be done under agreements that can vary from having the first tenant being held responsible, as in the case of simply sub-letting, or the owner could agree to only hold the tenant in possession,which is not so likely.

This prevents a default on the loans to make sure you maintain possession.

A foreclosure, judicial or non judicial, doesn't restore possession in CA.

You may take physical custody of the original note as endorsed and you may give that to the servicer for custody or retain possession and put that in a safe, like a safe deposit box.Then you receive the request to accept the deed from the borrower and the quit claim deed can be made.