when fishing a swimbait on a spinnerbait,is it best to remove the skirt or leave it on?

You can do both. I have tried this before and liked the performance/appearance of the bait when I trim/thin the skirt if using a swimbait on a spinnerbait. However, I prefer either one or the other and not mixing the two. My 0.02

Like Jason said, both will catch you fish. But I think just the swimbait alone might be a bit better.

I have a friend who used to slay them fishing this way, a small swimbait on a spinnerbait.

If you are looking to add a little flash to your swimbaits, I would recommend using a swarming hornet and live magic shad  8-)

If you are looking to add a little flash to your swimbaits, I would recommend using a swarming hornet and live magic shad 8-)

+1 this was going to be my suggestion. If you're going to take the entire skirt off the spinnerbait, why not buy a swarming hornet fish head spin? I guess you may have more flash and blade variety with the spinnerbaits...but I love the swarming hornets.

I think spinners and soft swimbaits go very well together. For deep water, post spawn SMB, this is what I toss:

This is basically a large, 1 oz. LedgeBuster Spinnerbait, with a Bass Magic attached to it. Slow rolling works well during this period. But I imagine the Swormin' Hornet dressed the same way would give you equal results as well.

i do very well with that rig without a skirt. similar to Crestliners rig but with double willows.  especially in murky waters. i do agree however they catch fish both ways. good bait for high pressured waters