I used to put dandelions inside of a composting barrel with lawns clippings, unwanted junk mail (paper), etc...
However, the dandelions survived the composting process.
I would put the dandelions in the trash, except that I am trying to avoid making the landfills and garbage dumps larger. I would prefer to transform dead dandelions into compost or fertilizer or some other soil amendment.
If I put blooming dandelions in a bucket of cold water for 30 days will the seeds and roots die?