First check if there's some dental floss left between your front teeth.
Spits in sibilants are much harder to see than spits in vowels as the waveform is irregular already in all kinds of hissing sounds. The good news is that sibilants are the easiest to edit/replace because of that random nature. If you cut from one take to the other during a vowel, you will likely get a click. If you do the same during a sibilant, it will work right away in 9 of 10 cases.
So my two suggestions are
- work on your pronounciation so spits don't appear to begin with
- replace spoiled sibilants with clean ones from another take or section