time to cut them?

time to cut this yellow shit?

I give them a very light tug, if they come off fine if not I leave them on the plant. Eventually they will fall off.

Just leave it, they are still providing energy for the plant, they will fall off as nature intended anyway.

I always leave them until they are wilting over and turning brown. They are still providing energy as stated before. Once they are dead they release a toxic gas durin decay. This is harmfull to your plant, so keep an eye on them.