What would you NOT buy pre-lived?

A mattress! I saw a documentary once about baby products and apparently the mattress, no matter how you clean or sun, there are just some things that live in the fibres that simply cannot die out. They shone a dark light on a seemingly clean secondhand mattress and the results were quite scary...

Undies only. The rest so long as can clean and wash, am fine. Bras also but if nursing bra, am fine though cos no idea how long will be breastfeeding though. Of cos, will also look at the condition of those items.

socks, gloves