Aluminum bottles are ubiquitous these days and therefore very easy to lose in public spaces. Labeling bottles with permanent marker or tape is a solid short term solution, but will wear off over time. Laser etching a water bottle with an anodized aluminum finish not only provides an aesthetically pleasing solution, but is also permanent. This approach takes advantage of an Epilog laser cutter with a rotary attachment to and takes approximately 6 minutes to do (per bottle).
: I made it at Techshop and I highly recommend anyone near one to check them
1 Anodized Aluminum Bottle: I bought mine directly from the Techshop, but here's an equivalent one
1 Epilog Laser Cutter (or equivalent laser cutter that can handle rotary attachments)
1 Rotary Attachment (I used the Techshop's rotary tool, and I believe it came with the laser cutter)
LAS101: Laser Cutting and Etching SBU
LAS201: Laser Engraver Rotary Attachment SBU