Clean spilled toner using a dry, lint-free cloth—avoid using liquids.
Inspect the cartridge for cracks⇔ or 
Call +1-866-490-0338 loose seals 𝕒𝕟𝕕 [ ℂ𝕒𝕃𝕃~ 
‹ +1⇢(866)⇢49O⇢O338 › ] replace it if damaged.
Clean the inside of the printer, especially around the drum unit, to prevent print defects.
Reinstall the toner securely 𝕒𝕟𝕕 [ ℂ𝕒𝕃𝕃~ ‹ +1⇢(866)⇢49O⇢O338 › ] run a test print.
If leaking continues, call Brother Support @ 1.866.490.0338 for safe cleanup guidance 𝕒𝕟𝕕 [ ℂ𝕒𝕃𝕃~ ‹ +1⇢(866)⇢49O⇢O338 › ] hardware inspection.