I am forwarding below a question from a colleague.   A picture was attached:  it shows the interior of the snorkel that is lined with “black muck/solids”.

I have a question about lab snorkels.  Recently one came open (at the joint), and I looked inside.  I have attached the picture of what I saw.   There is black lint, and it probably looks like the inside of a dryer vent. 

I wondered if we should be concerned about this?  Should we try and clean it ourselves, or is it better to have it professionally cleaned?  Are there any immediate safety concerns? 

I seek authoritative answers.

Thanks

Dave