Hey Tyler I have a 2 step answer for you here.
Step 1: Train your staff to refer anything not pertaining to regular business practice to a designated person who is trained to deal with these types of calls. If noone has been established in this regard then either appoint someone with a high level of common sense or have them redirect all calls to yourself. If you have a person in mind, train that person to take a message for the person who has the authority to make business decisions. Tell the caller that such authority is not available and have them leave a return phone number and that their message will passed along. Always use a ficticious name for the person who makes the decisions like say Frank Rizzo. This will serve 2 purposes.
1. The ficticious name will probably get junk mail at which can be easily identified and disposed of as it will be spam mail.
2. You never have to worry about getting caught up in a scam, and most likely they will never leave a return phone number unless it is legit.
Step 2: Use the "Dont call us, we'll call you" tactics, and never return a call unless you wish to do business with them.
Once this has been implemented and has been in effect for a period of time, the callers will give up and move on to the next poor sap, thus leaving you in peace. In addition you can relax knowing you will never get scammed or bothered ever again.
If you havent noticed, I am somewhat of an expert on detering scam artist.
Edit: I almost forgot one very important rule. Teach the designated appointee that the business decision maker is NEVER available for immediate conferences.
Practicing this method will prevent any confrontations with solictors even though your first instinct would be to give them a piece of your mind. Actually you can rest assured, you will have the last laugh cause more than likely you will crack up at the junk mail you get in a ficticious name that dont exist.
This is a proven strategy for handling soliciting annoyances.