I occasionally mix them all depends on how much I have left if there's enough to get me going then no if it was the shitty coke like I've been getting yea but it doesn't enhance the high so I don't see the difference if you do or you don't
I wouldn't. There can be cuts that can spoil your coke. Have you ever left it out and seen it turn into brown or yellow slime?
If I have some coke that's somewhat old or that is from a different source as most of mine, I mix it with water and put it in a nasal inhaler.