I've had my little kitchen compost unit for some years now and the little plastic silicone holders either started to break or got lost. Since I didn't see any models out there for this, I was able to design it in fusion.
I printed on the flat back side with some auto tree supports, but it might work fine without. I used PLA.
Polder_Kitchen_Compost_Silicone_Holder_Part.stl | 932.9KB |