Engaging with un-wired/ non-desk employees

Good afternoon, I am having some challenges engaging with client members who work more traditional blue-color jobs (no email, shift work, not interested etc). When we have good emails available for the population, we are extremely successful. However, when this digital component is missing we have to get more creative. We are currently using direct mail, calling campaigns, targeted Facebook ads, site visits etc. but I would love to hear if any community members have found other ways to engage non-desk workers. Would love to hear what's worked, what hasn't worked and I would love to help anyone that is thinking about implementing these engagement strategies. 

Cheers,