On 2 Oct, 21:41, JakeD wrote:

Unfortunately, it's been sitting there with lids on for several years,
and now looks like a grim, brown slimey mess, with an inch or two of
liquid on top!

My dad, who was not a gardener by any stretch of the imagination, used
to put grass cuttings in an old galavnised tank which filled with
rainwater. It seemed to rot into a brown liquour, not unlike silage
slurry, which he diluted with 75% rain water and used on the garden as
a fertiliser.

it did no harm, and probably a lot of good.

The dry sludge got dug out at the end of august and dug into the next
year's potato beds, with apparant success.