Chris Hogg explained :
On Sat, 24 Apr 2021 13:47:06 +0100, Harry Bloomfield, Esq.
wrote:

In my sprayer I have some diluted Rosate 360 TF according to
instructions, left over from last year. Will it still work this year
please, or do I need to make up a fresh batch?

It's basically glyphosate, so should be OK. But you've nothing to lose
apart from the time spent re-spraying with fresh if the old stuff
doesn't work.

Ta!