The iMac has the biggest screen so the kids Zoom on that the most and it is FILTHY with loads of greasy smears. Some of which are from cats rubbing it while the kids are doing lessons. One of our cats is a complete tart for a class full of children cooing at him. 
I'm a bit scared of damaging it so I've been quite timid in terms of product and elbow grease.
For phones and iPads I just use a tiny amount of any old spray cleaner on them and it's been fine.
But the glass cleaner and bathroom spray I've tried on this big screen so far have just spread it out.
Has anyone cleaned a disgusting filthy desk top screen successfully?