How to delete unusued files?

[hermesaudio]

Xara WebDesigner pro+ 20.2

Wintel 32gbram i7, 250Gb ssd/2TBSata

I've designed my own web site, but Analytics is warning me about a lot of unusued elements (css, js, pics, fonts) that slows dramatically the loading time.

Now, please, do you know if there is a way to get rid of all the unusued elements for good?

Thanks in advance

Best regards

Hermes