Jeyes fluid will kill off the compost completely rendering it absolutely useless. Spread the spent compost around the garden or in your compost bin.

No it will destroy any plants you try to go in it. Jeyes fluid is a structure steriliser, staging/glass etc.

And if your tomatoes suffered from blight this year, I would bag it and bin it--it couldn't be used again unless steam sterilized, which is difficult for home gardeners.