Ahhh ni storage stains la, memang annoying! A few of my mum friends yang ada baju simpan lama try soaking with white vinegar and baking soda paste dulu before normal wash, one of them kata it works best compared to bleach because gentle sikit pada fabric, especially kalau baju old ones like yours. Another trick yang ramai pakai is oxygen-based bleach (like OxiClean) soak overnight, then wash, boleh juga try sunning the clothes after treatment sebab UV membantu fading those yellow spots, it's natural whitener. My personal go-to untuk stubborn stains is just the vinegar + baking soda combo with a soft brush dab gently, then normal wash, lebih selamat dari harsh chemicals. Give it a try on one baju dulu to test sebelum semua, tak rugi pun!