Let’s talk contamination!
Contamination in the compost world is when we find an item that doesn’t break down, release CO2 and supply useful nutrients to our plants and soil.
If you come to our Community Sift Days you may have the job of pulling bits and pieces of plastic, string, stickers and what we call, crunchy plastics, out of our finished compost. These are what we call contaminants.
Contaminants don’t usually start out small either. But once they enter our compost system they get covered in rotting food, break apart and physically deteriorate from the turning and high temperatures of our piles. Yet, it is unlikely these materials will fully break down in our lifetime or add any benefits to our soil. Even if a material seems to disappear we aren’t sure if it left a toxic residue behind or just broke down to smaller than the eye can see.
While we all want to do the right thing and feel good about composting the most we can, when non compostable materials are put in our system it can take much more energy to remove it (if still possible). We are on a mission to reduce contamination and we hope you will help us.
Please review the list below and spread the word in your household.
Our favorite motto: When in doubt, keep it out!
Contaminants
Colorful cardboard-like materials such as food packaging and soda can boxes - many of these have plastic films on them and it has become too difficult to discern between the infinite brands.
“Compostable” green bags - since we have not seen the brand or box they came in we cannot be sure that the bags are truly compostable in our system. We typically end up sifting and throwing them out. If using these bags in your small countertop system please empty the food contents into your bucket and dispose of the bag.
Produce stickers - these are typically PLASTIC and much easier to remove or cut off of firm, fresh produce than on soggy, decomposing produce.
Tea bags - too many brands, too much plastic - beware of dipping plastic tea bags in boiling water too. We suggest using loose leaf in a tea infuser or a french press
Rubber bands - these commonly bundle up your herbs and produce so please remove before putting in your bucket, they become much more difficult to remove after food has become rotten and soft.
Rubber or latex gloves - these are not compostable and can be thrown in the trash
Wax paper, pastry paper, wet wipes, etc. - while we can accept common white kitchen paper towels, we are finding more and more different types of “paper towel” like materials that are not compostable.
CAN - Put in the bucket
Cooked and raw foods
Fruits and vegetable scraps
Coffee grounds and filters
Rice, bread, oatmeal, grains
Meat, bones, fish, crustaceans*
Dairy products including cheese*
Sauces, syrup, and oil*
Loose leaf tea and tea bags (no plastic/nylon)
Herbs, spices, dried fruit
Small-kind green waste/household plants
Tortillas, potato chips, popcorn
Stale crackers, bread, cereal, pretzels, pasta
Nuts and shells
Tofu and tempeh
Hair (pet or human)
Paper plates, bags, & to-go boxes (no bioplastics)
Newspaper (remove plastic/shiny inserts)
*Keep under 5% of total.
NO CAN - Recycle or put in trash
Glass
Liquids
PLASTIC
Dryer lint (polyester is plastic)
Very salty foods
Aluminum cans or foil
Latex or rubber gloves
Produce stickers/label & rubber bands
Paper plates or coffee cups with wax coating
Fats, grease, oil, candy
Cloth and clothing
Bioplastics:
Items labeled biodegradable
Items labeled BPI Certified Compostable
Items labeled ASTM D6400 or D6868
Styrofoam
Baby wipes
Pet food
Cigarette butts
Dead animals