How to clear leaflet layer after click

I'm new about leaflet a I try to select/deselect layer using a mouse click. Firstly mi map is in this way

After click on a layer i want to select it and highlight

Now if i again click on previos select layer i want to deselect it and reset the highlight. This is the code that i use to do this.

  onEachFeature: function(feature,layer) {

      layer.setStyle({fillOpacity: 0.0 , color: '#424a44', weight: 2});
      layer.on('click', function(e) {

      let isLayerAlreadySelected =  // Some logic to undestand if layer alreeady selected

      if(isLayerAlreadySelected) 
         layer.setStyle({fillOpacity: 0.0 , color: '#424a44', weight: 2});
      else
          layer.setStyle({fillOpacity: 0.4 , color: '#004691', weight: 3});
      }

  }

but sometimes when i try to deselect a layer previously selected the layer style in not resel the opacity remain. Some suggestion about this?

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