I, like many of the members, like to keep our precious optics clean and dust free (it's especially important for me when we have reflective gratings involved).
The Rocket hand blower and photographic blower brush are good but it's always better to have a high pressure clean air blower.
I found some eBay canisters can be a problem - leaving residues etc.
The solution I use and highly recommend is the MG Chemicals "Super Duster 134"
This works 100%, non inflammable, no residue.
Available in Australia through Mektronics, Sydney
www.mektronics.com.au