Spiders webs can easily render a CCTV camera useless at night. As soon as the infra red LED’s are illuminated the light is reflected back at the camera and the picture is virtually useless!
I have tried brushing the cobwebs away, but often the spider is out within a matter of minutes re-spinning the web! I’ve been using a product that I bought on ebay called spider X and so far this has prevented the spiders from coming back. Once applied the spider X lasts for several weeks, so it is well worth applying it.
You might know of a cheaper home-made product, so if you do please post in the comments below and I’ll try it at some point.