Ask your farm vet for a DOOP bin (stands for Disposal Of Old Pharmaceuticals). I have two, one sharps bin and a seperate one for medicines. You pay for the bin but when its full you just drop it off and exchange it for a new one you dont have to pay for them to take it. I cant remeber how much it is but its not expensive at all. They come in different sizes, I tend to get the largest one so it lasts a while and can fit larger items like drenches in (the smaller ones cant). When you are recording how the medicine was disposed of in your medicine record book you can just write DOOP bin. Hope that helps!