The Valet Autostrop safety razor (1906-1946) must be one of the most 'sustainable' safety razors that were ever made, it was designed with a replaceable blade system that obviously had no plastic in it, but wait for it.....you could also strop/hone your 'disposable blades' with a small leather strop when they become dull, extending their use well beyond that of its normal life expectancy, even as long as a year or longer on a single blade! These razors have a cool steam punk design about them that was also functional and certainly made to last, the tray of this razor is made from solid 1.2 mm brass, for crying out loud, carports nowadays are made from shoddy 0.35 mm sheeting!
The problem with most of these razors is that the leather strops have deteriorated to such an extent that they are no longer useable, however it is fairly easy to make one if you can get your hands on some 1.6 mm leather. Most folks will probably opt for simply replacing the blades when needed, as they are quite cheap compared to cartridge system blades. The VC4 model in the range has the teardrop clamps for blade retention and a solid safety bar, the latter being the only change from the VC3 model.
A nice thread explaining all the models can be accessed here.
Here, here and here are some more vids on stropping and different blade options for this series of razors.
The razor weighs 65 grams and stands 90 mm high.