Allsop Clear View Gel for cleaning the screen?

I bought Allsop Clear View Gel and included wiper for cleaning the 15" screen, but I started having doubts when I got home as I noticed it's gel. Is it good for clearing for example keyboard marks off the screen, and how does it actually work? Does it leave something on the screen?

Here's a link to the product, mine isn't exactly the same packaging, but seems to be the same basic product. Mine has for example a Titanium PowerBook printed in the label.

http://www.allsop.com/cd-dvd-cleaners/computer-maintenance/model-25048/clear-vie w-gel/