Once again, the misuse of nonprofit organizations to shield income or provide fake tax breaks has appeared on the Internal Revenue Service’s Dirty Dozen, the agency’s annual list of the top 12 tax scams in the United States.

Most of the abuse stems from people giving money or property to donor-advised funds or similar programs while retaining too much control over the donations. The IRS also warns charities to watch out for people overestimating the value of donated property, such as land or artwork, so that the donors can take an excessive tax break.

In addition, the IRS says that an old scam — claiming that private tuition payments are donations to a nonprofit group or religious organization — continues to grow. The agency noted on last year’s Dirty Dozen list that the scam had returned, and this year it notes that it has gained popularity.