what an embarrassing call

Treating your Gatekeeper as a Stakeholder:

It is inevitable that if you send a fax or a letter that the communication will be received by an admin/assistant and not your stakeholder - which I guess in this case is the purchasing manager. In my current role I have sales people calling on me every week, and personally I do not care for unsolicited emails or faxes.

I spent my career selling technology - so likely a little different than your world - none-the-less I had significant success treating executive assistants and admins as stakeholders instead of trying to do the end-run around them.

Just try this a few times - call in and ask for the admin assistant for the purchasing manager instead of the purchasing manager. Then tell him or her what you do, how you thought there may be an opportunity to help XYZ company by <whatever>, and that you wanted his/her permission to send them a fax or email discussing how you can help and review it with a follow up call - then he or she can decide after you review it if it made sense to set up a discussion with the purchasing manager.

(a) this approach takes the assistant so off-guard because they get so many calls per day from sales guys just like you trying to do an end-run around them.
(b) some will not be receptive, but you will be surprised how many will not only be receptive, but will be helpful in teeing up the introduction you are looking for (and maybe even coaching you in the process).

Like I said, me selling software and technology is certainly different environment than the poly tarp space, but you may be surprised at how effective the technique can be.

Eric