To many people, this time of year is synonymous with “giving.”

It’s a season that brings out the best in us; we give thanks, we give gifts, and we give to those who are less fortunate than we.

However, it’s also a season that brings out the worst in others. They know a lot of people are in a giving sort of mood, and they take advantage of it. It seems like for every charity providing money and services to those in need, there is at least one organization whose primary mission is to line its own pockets. So how do you avoid charity scams during the holidays and throughout the year?

One of the best ways to give is to simply decide ahead of time which organizations you’re donating to this year, and make your contribution by contacting them directly. When a representative of another charity approaches or calls, simply explain that you’ve already made your contributions for the year. Many people give in this way, so they should be polite and accept your answer. A rude or hostile response is a sign of a charity that isn’t on the up-and-up.

You can also donate something other than money. Clothing and food are always popular items, or you can choose to help out where it is needed. Ask around—I can guarantee somebody needs you somewhere. Plus, donations of time and effort can be more rewarding than monetary giving, as they can bring new experiences and face-to-face contact with the people you’re helping.

Be wary of charities that contact you by email, unless you’ve given in the past and provided this information. Unsolicited email is always pretty sketchy to begin with; clicking on a link and providing credit card or other information can lead you straight into identity theft. However, if you gave to an organization before and provided your email, they may use it to contact you in the future, since it saves money on postage.

If someone approaches you in person or calls, be sure to ask what percentage of funds goes to the people the charity serves. A legitimate charity should expect this question and equip its callers, whether volunteers or paid employees, to answer it truthfully. The question is almost a litmus test in itself—every organization has operating expenses, so an answer like “100%” probably isn’t true, and as always a hostile or evasive response is a sign of a crooked charity. Ask for information to be sent to you, or ask for a website address, because you’re not going to give your credit card information to someone over the phone no matter who they claim to be, are you?

Donating by check is better than cash, because it gives you a way to track your donation. However, writing a check also puts your checking account number into someone else’s hands. If you trust the organization, that’s your call to make, but for an extra level of safety a cashier’s check is even better—even a legitimate charity can misplace a check or have its office burglarized. Finally, when it comes to checks, always make the check out to the charity, not an individual, and never trust anyone who tries to get you to make a check out to “CAS,” no matter what the initials supposedly stand for. All a thief has to do is add an “H” and they’ve got a check, from you, made out to “CASH.”

Do your homework before you give a single dime to anyone. Check out charities with the Better Business Bureau or Charity Navigator. Don’t assume that nonprofit status means anything, since crooked charities hide behind this designation. Finally, pay attention to the name of the charity—the difference between “Foundation” and “Fund” can be the difference between helping those in need and helping a thief buy a spare Jaguar.