I use rainx
but the problem is the smear when the wipers are used
I have honestly never ever cleaned my wipers and never had a smear....
I recon there is a slight imperfection on the wiper, it would wind me up too and I would just buy a new wiper...
they are new wipers - it was happening on the originals - so replaced them and still happening !!
so if this doesn't work.........I'll have no other choice but to scrap the car