Best Method of Reaching Out to Companies

[mfine]

My team is starting their fundraising efforts, and I was wondering the most effective way of reaching out to local companies.Sending out emails is the fastest, but many companies don't list appropriate emails, and it probably has the lowest conversion rate. Letters probably have a similar conversion rate, but every company has a mailing address, though letters do take longer to send. Calling them would probably improve the conversion rate, but that takes a while, and they may not have anyone with authority to make those decisions. Finally, reaching out in person would take the longest, but also have the highest conversion rate, though it has the same problem that there's no one there to talk to.

So, what have you found to be the best way to reach out to companies?