You can clean it yourself. The sensor has a cover glass over the face of it, not to be confused with the sensor compartment glass. There are commercial sensor cleaning swabs available Online with are used to clean DSLR sensors, they work fine. They are a microfiber cloth over a flat plastic stick, with a cleaning fluid in them, one wipe and it's clean.
Here is one example:
https://www.amazon.com.au/VSGO-Camer...29279754&psc=1
I used those sensor cleaners on my ASI1600 mm c for years, no issues.
I would suggest you just put in New dessicant if you can get them, in my experience thry can become chalky if reheated and produce dust.
It is an easy DIY job.