You have just recorded vocals, you did not forget the anti-pop filter BUT
some harsh sounds still remain. sss
How to get rid of those annoying sibilances, harsh sound on “s” “ss” “sh” “ch” “z” ?

When it comes to reducing excess sibilance (“ess” and “shh” sounds) from vocal tracks, nothing compares to Waves DeEsser. Inspired by vintage gear for precision de-essing and high frequency limiting, DeEsser delivers smooth and natural output with minimum fuss. Check out all De-Esser plugins out Plugin Deals 3.5 million sounds w/ Loopcloud Free Trial http. FabFilter Pro-DS is an intelligent and transparent de-esser plug-in. Available in VST, VST3, AU, AAX and AudioSuite formats for Windows and macOS. FabFilter Pro DS ($179) With its ‘Single Vocal’ detection algorithm, FabFilter Pro-DS accurately.

VST Spitfish is a dead-easy to use de-esser. Aimed mainly at mono or stereo vocal tracks. Just like classic analog de-essers, this unit dynamically filters out harsh, annoying s-like sounds that would otherwise 'spit' in your face.

=> You can edit by hand if you have time, but it can be very tedioussss !

Or you can use a DE-ESSER, for automatically remove those annoying “s” in your vocal.
We have selected 3 FREE VST plugins you can use in Wavosaur or any audio editor or sequencer, that does the job ! let’s go :

1. Spitfish

download for free ! => http://www.digitalfishphones.com/main.php?item=2&subItem=5

Best De Esser Plugin

The gool old VST by DigitalFishPhones, it’s dead simple, and nothing prevents you from using two Spitfish in serie. Free cymbal vst. It removes efficiently the “sss” sound.

Free Vst De Esser Plugin

2. Lisp

Sleepy Time List VST

Information and download : http://sleepytimedsp.com/software/lisp/

/vst-plugins-fl-studio-trap.html. This one comes with VST2 and VST3 version, as well as a 64 bit version!
Like spitfish, it has a stereo mode, and you can adjust the frequency for detecting the sibilant parts.
There are not so much freeware de-esser, this one is nice!

3. Tonmann de-esser

Direct download => http://www.tonmann.com/temp/Tonmann_DeEsser11.rar

De Esser Plugin Audacity

This one has been made with synthedit surely. We didn’t give so much test but it seems to do the job! It has a clean and simple interface.