I guess she still cleans them from time to time. I do, and they just make new webs.
Only very old webs are ... dirty.
Yeah I thought spider webs only lasted a few days before they had to be torn down and rebuilt (because dusty webs aren’t effective nets)?
Yes, I believe the spiders even eat their own webs and then produce new ones. But there always remain parts amd spiders die, change place etc. So old ones still remain.