Hi
I suggest you use this video as a guide on taking the lens apart
[link|https://m.youtube.com/watch?v=AhpHc8xgcRY|https://m.youtube.com/watch?v=AhpHc8xgcRY|new_window=true]
As for cleaning the lens I suggest lens cleaner of isopropyl alcohol ,Qtips/cotton buds or a microfibre cloth
Make sure to clean the lens carefully scratches can cause the image to look off or to be slightly distorted
Hopefully this helps
Any questions please ask
Thanks:-)