Physic props without physics

I haven't done any Source work for years, but I remember there used to be a flag you could enable or disable in the object properties to disable physics... sorry I can't be of any more help, but I'm pretty sure it's possible.

Yep, there's a 'motion disabled' flag on prop_physics

Check the model's properties in Hammer model viewer; many physics props are compiled with "allow static" flag and if this is the case, you can set this prop to prop_static.

If allow static is not there and the model is purely physics, then set the entity to prop_dynamic_override. The physics will be completely disabled (not just unmovable) and you would save a bit of engine resources since dynamic props are cheaper than physics.

prop_dynamic?

prop_dynamic_override or prop_dynamic_multiplayer and play with flags, i disable player col for small shit like cans and cones etc but keep 'em dynamic so they get affected by bullets and grenades, works pretty good...