The next time you travel on a long-haul flight, be sure to bring your own blanket in your carry-on.

You may be used to those cozy airline-provided blankets, but you may want to avoid them entirely after an anonymous flight attendant took to Reddit to spill dirty airline secrets.

According to the Reddit user, by the name of mehow4, some airlines don’t even bother to clean or swap blankets between flights. This means that you could be covering yourself up in someone else’s germs.

“I worked for Southwest as a flight attendant. Those blankets and pillows? Yeah, those just get refolded and stuffed back in the bins between flights. Only fresh ones I ever saw were on a first flight in the morning in a provisioning city,” the user stated.  “Also, if you have ever spread your peanuts on your tray and eaten, or really just touched your tray at all, you have more than likely ingested baby poo. I saw more dirty diapers laid out on those trays than food. And those trays, yeah, never saw them cleaned or sanitized once.”

Even if the blanket is dressed in plastic packaging, you should still use them with caution. Back in 2000, the Union of Needletrades, Industrial, and Textile Employees, which supplies blankets to major domestic airlines, accused clients of repackaging without cleaning, according to a report from Bravo.

Back in 2007, The Wall Street Journal released a report that revealed most airlines only cleaned their blankets every five to 30 days.  The investigative reporting team also found traces of bacteria that could lead to infections and pneumonia.

The controversy has caused airlines like JetBlue and American Airlines charge passengers for them to ensure that customers are getting a fresh one to take home.

Even with the changes, it’s not worth the risk of getting sick. The best way to stay warm and cozy on your next flight while avoiding germs is to simply purchase and bring your own.