How long is the expiration date of the mascara?

pu1. I can't keep using it
If you leave it open for a long time, it starts to oxidize and it's not good

2018-07-30

OK

pu2. I don't know the expiration date, but I tend to throw it away when it gets clumpy

2018-07-30

OK

pu4. If I use it for about 3 months, it gets clumpy, so I naturally throw it away

2018-07-30

OK