Here's a can of worms ~ lens cleaning

[JBW]

Of course, there is always the old fashioned way to clean using soap and water,

https://www.youtube.com/watch?v=lrdkFXsr5Us

looks good to me.

[Tronhard]

With regards to Manfred's scary video on cleaning a camera and lens....

Years ago I was doing IT support for a coal mining company. The PCs from the mining area would come up totally covered in coal dust, and when opened they were full of black dust. After a lot of air blowing I discovered that the best thing to clean them up was to disconnect any internal power source and put them through the dish washer for a couple of cycles. After leaving them in a warm room for a day or so they came up clean and good as new or ready to work on!