Yow!

I'm getting myself hyped up to rake and spike the front lawn.
A few years ago I used Evergreen complete 4 in 1, I know that you don't
think much of it.
I would have used this stuff in the summer. It killed the moss allright, the
dead moss looked awful so I never used it again.
Thing is that I've got loads left. The instructions say to use between April
and September..............
Would it actually do any harm or good to use it in the next few days when I
rake and spike the lawn and should I use it before or after the
raking/spiking?

Taa.