VINNIES is urging people to stop leaving items outside donation bins, as dumped goods make easy pickings for thieves.
Retail operations manager Gail Mountney said people should donate in store during opening hours or wait until bins were emptied to make sure their items ended up on store shelves.
Other charities also face issues with dumping, including Lifeline, whose bins at Wellington Point were overflowing last week with items like shoes, clothes and books.
"We tend to find - particularly on the bayside - that over the holiday period and on weekends, we (Vinnies) will often get large amounts of donations dropped off," Ms Mountney said.
"Presumably, the person has dropped those off with the good intentions that we would be able to sell them and make a profit for our programs.
"But very often when they are left out overnight people go through them, scatter them over the car parks and down the pavements. It is very annoying for the other retailers we are next to.
"We have a group of people at Capalaba at the moment that actually take the donations around the corner, hide behind a bin, try them on and leave what they don't want. Unfortunately a lot of that goes on."
Vinnies received a number of donations during the Christmas holidays, but Ms Mountney said people needed to be conscious of what they were handing over.
"We are calling for Queenslanders to donate good quality items that we can actually sell," she said.
"We always say to people, 'think about what you would and wouldn't give to a family member or one of your best friends'.
"Clothes with holes, rips, stains and tears, we can't sell those. Then that becomes a problem for us to try and recycle elsewhere or take to landfill.
"If we have to take things to the tip, obviously there is a cost involved in running a truck."
Profit made from donations sold in Vinnies stores was put towards a range of community programs.
Ms Mountney said the money was used for things like emergency assistance, support for the homeless, youth programs and disaster relief.
"We really work on trying to get people to donate during shop hours and in store," she said.
"If we are not open, please try and hold onto the donations until we are open or until we have the donation bins empty."
There are two Vinnies donation sites in the Redlands at St Rita's Primary School and St Luke's School.
Ms Mountney said ladies clothing and bric-a-brac were best sellers.
Read more local news here.