I have a Laptop that needs a really good clean - will this stuff be okay for a Laptop ? I have killed a few keyboards in my time and want to check before I do anything stupid.
What stuff do you mean - detach the battery first to avoid any unwanted activations. If your keyboard is that bad consider replacing it - approx £15 on Ebay and videos on youtube how to do it. You can also get moulded silicon covers to match most common keyboards to keep the crap out in the first place - they are not expensive either. otherwise any non corrosive cleaner and a can of air to blow it out.
I've used a similar product called Cyber Clean...does a good job.
I've given the keyboard a gentle vacuum with a soft brush first, then used the "gunk" as directed. It can be used several times as long as it's kept tightly sealed.