Another vote for plexus.
I'd be very slow to endorse washing up liquid. That is perhaps the harshest cleaner of all. A presurized pump type garden squirty bottle with water, and aircraft shampoo (Nuvite Citricut etc) and a bug remover sponge is ideal. Quick spray, wipe and then a synthetic microfiche cloth to finish. Jobs a good un.....Only reason I know washing up liquid is bad news is we have a own a plastics company.....specialist knowledge indeed.
Flying with a clean windshield is a joy!