Should I clean & lube slugs?

1- If the slugs are dirty then clean them if not I would not bother.

2- You will get many answers to that question as people swear by loads of different lubes.

3- Nothing wrong with silicon oil it is what I used for quite some time and it really cut down on my barrel cleaning. I am shooting the NSA slugs now and they come already lubed.
 
I got a couple boxes of slugs last week from a top slug maker (will remain nameless) I had to wash the lightest ones 5 times and the heavier ones 3! I inspected them and the lighter ones had all these little shavings in the hollow point. So much so that I am not going to shoot them. I sent pick so they could see. I lube with Slick 50 #1. Less cleaning I did notice more speed? donno