I’ve seen various ideas.
One is printed parts that bolt onto the wheels and add a sort of snowplow to clear chips and debris from in front of the wheels. One at each wheel pushes chips and dust off of the edge of the table as the LR advances.
There’s no real reason why a brush or similar appliance couldn’t be used, perhaps even just brushing off the tops of the wheels themselves would be adequate.
If you wanted to be extra sure, you could probably gear up circular brushes off of the wheels. Say a 3:1 ratio would be plenty to get good speed brushing off chips and dust. It would take some power off of the Y axis to do it, but that should be a relatively minor thing.
Regardless, you probably want to prevent stuff from entering between the wheels.
Angle iron would be cheaper than aluminum, and ought to do the job for fencing off the wheels, too. If you can get some lengths about 15-19mm high and attach them to the table just inside the wheel tracks that should do the job. Bonus, it also assists the LR’s Y axis tracking.