Heat detector help--yellow goo

[Franksandbeans]

I have what I believe is a fixed temperature heat detector installed on the ceiling of my garage. The detector is probably original to the house, about 30 years old. I want to remove this heat detector but the plastic casing is cracked and there is a yellow dried substance in the cracks. I am wondering if anyone knows what is inside a heat detector and if there is something toxic that has leaked inside the heat detector to cause this yellow goo to form. A photo is attached. Can anyone identify this goo or tell me if there is anything toxic in this type of heat detector?

 

[brevor]

I dont think anything is leaking from the heat detector, I think that is just 30 years of dirt buildup.

 

[davenn]

I tend to agree with brevor
plus it looks more like a smoke detector

For the cost of $10 - 15, I would buy a replacement
you should always have a good working smoke detector or 3

cheers
Dave