^ No cleaning the bed bars off is what you have to do don't have to be spotless, but you don't want any real big chunks - large masses. Just go over them with a chipping hammer. You need that molten spray to go down into the bed, not get bounced off crap back onto the bottom of the sheet. Also greatly helps to cut your own slats and have the points as pointy as possible and further apart and also as few a points as you can get away with, if your cutting big bits, you can easily remove 2 out of every 3 slats and just a point every say 6". Equally if your only doing thin sheet, make the points a lot steeper than the typical 90 degree saw tooth patten and make the gullets a bit deeper, only cut them in 2-3mm thick material too.
Am not a believer in copper slats, yeah there more resistant to the metal spray and beam damage especially on a co2, but that spray bouncing back onto the sheet is the real issue.
With 2 beds if your cutting mixed work its not all wrong to set them up with differing slats and be selective as to what work gets cut on which if your doing mixed stuff.
If you want quality cutting off a laser you have to get the basics right and that means frequent bed bar cleaning and slats to suit your work and even possibly changeing them from one type to anouther to suit your cutting. Way too many laser places are shit because all they focus on is through put and rely on the big spend on the laser to make great parts and fail on the basics.
We use to just use a water thinable anti splatter, its not perfect, but it sure makes part clean up a lot lot easier.