Looking for a way to 'inspire' your students to clean up after themselves, during lab time and otherwise?
Try using lab strikes.
Each of your classes is a team, competing against each of the other classes that comes in your room.
At the end of each class period, you walk around the room and take note of anything that's out of place: a piece of lab equipment not put away, a marker left on the table, a scrap of paper on the floor, etc.
Each one of those offenses is marked down as one strike. I keep a big poster of lab strikes hanging in the front of the room so everyone can see them. The poster is laminated, so I can mark on it, and then erase them and use the same poster over again.
At the end of the designated time (I use the end of the marking period, but you can shorten that if necessary), the class with the fewest lab strikes wins.
In order to keep the students focused and wanting to win, you want to make sure the prize is something valued by your students. It could be a homework pass. My students were particularly fond of homemade brownies. You have to be the judge of your students' desires and what you're willing to do.