We use the Evergreen 80 weed & feed lawn mixture which is spread on the grass in the Spring and this generally gets rid of most of the clover. However, I suspect that putting this type of preparation on the clover at this time of year won't be too successful as the plant has to be growing strongly, when it virtually grows itself to death. Whatever preparation you use, avoid about putting any clippings on your compost heap for about six cuttings as even when it rots down the chemicals can stay in the compost and ruin your plants.