Fertilisers and feed

I make both comfrey and weed tea but rather haphazardly, i.e. bung the stuff in a bucket with a bit of water the ladle it out to dilute it if I remember to use it. Weed tea is the result of being lazy. The handfuls of weeds from random weeding get drowned in a covered tub because I can't be bothered to take them to the green bin. Question: is last years 'tea' still usable? It smells vile enough!