Our organic cotton inner lining may linger in markings over repeated use and this is not uncommon and indeed normal. You can rest assured they will be sufficiently cleaned if following our washing routine. Marks that can cause concern are potential mould spots which will appear as small spots in dark green/dark grey/black. This will be due to insufficient washing routine or when pads were not sufficiently dried before storing away in between uses.  We recommend using Tuffy Stain Remover bars for optimum stain removal.