There have been two other threads in the last two days with exactly this problem. The posters pulled the lights, and were stunned by the yuck that came out.
Pull the lights, scrub it good, and put them back. Kill the power at the breaker and the switch before you start. Post pictures if you have questions.
Pull the lights, scrub it good, and put them back. Kill the power at the breaker and the switch before you start. Post pictures if you have questions.