Dirt and moisture in theta red dot

[Wegalaxy]

Hello,

I bought a pre owned theta red dot. 

Looks like there is dirt and moisture inside the lence after I played in very heavy rain.

Is there any way to disassemble these red dots or is there a way to dry them out?

The exact model:

https://www.patrolbase.co.uk/theta-optics-compact-ii-raised-reflex-sight-replica-for-20mm-ris-ras-rail

Thanks