I mix isopropy alcohol and purified water from the grocery store at a 50/50 mix in a tiny spritz bottle from CVS that u bought for 2 dollars. It cost a dollar for the alcohol, dollar for the water, and 2 dollars for the spray bottle. I still have 90 percent of the alcohol in the original bottle and my spritz solution has been used a lot over the last few months and is sill nearly full. This should last the lifetime of my computer and is very cost effective. I used to use my good buddy's iKlear but found it was streaky and took longer to evaporate, so now this is what I use. It evaporated faster and is much cheaper, and does a better job on touch stains or dried on stuff.