I use them occasionally on St. Clair. Usually in the summer when the weeds are getting close to the top of the water. The rig is light enough to keep it right over the top of the weeds and just below the surface.
I have purchased the new Berkley Gulp in Natural Crawler color for this very purpose. I don't know how well it will work but I need to do something to keep my kids from spilling dirt all over my boat carpet
i have used plastics on harnesses in the saginaw bay for about 5 years now. I don't seem to catch as many fish but it does work to keep the junk fish off a little better. Also with the plastics you don't have to check your bait as often for weeds and little perch
I hate getting that dirt on the carpet in my boat too even though it is a fishing boat. What I do is keep my crawlers in my live bait well where I have a water supply. This keeps them out of the sun. I also bring along something like a cool whip container or larger and fill it up with water and leave it in the livewell too. I then put about a half a dozen crawlers in the water which cleans them and allows them to take on water and plump out. It saves the carpet and keeps the hands cleaner too. I just change the water regularly which keeps them cooler and cleaner. As someone else said on this site, keeping them in water doesn't hurt them at all.