On my helmet faceshields:
Get it wet, apply a soft soap (either dish soap or hand soap, whichever is handy), smear it around by hand, scrape stubborn bugs off with the edge of a finger nail (still plenty of soapy solution), rinse, dry with a soft, clean cloth.
(Do NOT use paper towels)
The windscreen:
Spray with Honda spray cleaner/polish and wipe clean with a soft, clean cloth.
I have used the Honda cleaner on faceshields when on the road and away from a source of running water and/or soft soap.