Do not push a brush into an unfamiliar disposer or use one while the appliance is powered. Use only the tools, access points and cleaning method explicitly allowed by the exact model's instructions.
What the observation tells you
A brush can snag, shed material or conceal how far your hand has entered the opening. Electrical isolation does not remove sharp objects that might already be inside. The visible sink flange can usually be approached separately from the hidden mechanism.
A useful next step
Limit cleaning to approved accessible surfaces and removable accessories. If residue cannot be reached by that method, arrange service rather than improvising a deeper cleaning tool.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.