“If you’re good at something, never do it for free.”

This sentiment didn’t work out for the joker in the latest Batman movie and it doesn’t hold true for workers wading through today’s job market, where many mid-career professionals can find success through unpaid internships.

According to career coach and co-founder of the Institute for Coaching Meredith Haberfeld, these unpaid stints can be great for filling holes in both your resumé and your professional network.

“If you’re savvy and disciplined about cultivating genuine relationships within the company and more widely in the industry, among the most useful outcomes of mid-career internships are the contacts you develop,” Haberfeld says.

Also, interns can use those contacts to help in a future career search by getting a senior member of the company to review your resumé.

Beyond networking, the most important thing to do during an internship is to “accumulate specific, measurable results for the organization that you’re in.”

And it’s these accomplishments, she says, that should appear on your resumé.

“List it as the role that you’re performing, not unpaid internship,” Haberfeld says. “If asked, ‘What was your salary or was it a paid position?,’ obviously be honest. But I wouldn’t recommend highlighting that it was unpaid.”

While many companies may not advertise internships to mid-career professionals, she says it’s always possible for you to create an opportunity by creating a very specific articulation (two-sentence maximum) of what you want and why you could do it well.

A candidate then needs to send that to various contacts, followed by, “Who do you know that I could speak to about this?"

Haberfeld advises making three connections every weekday in this fashion. At 60 contacts a month, it’s bound to find someone who can help.