1001 carpet cleaner

I have always thought I was a clean bear, but after having to endure another tumble in the washing machine I have come to the conclusion that I have to stop being a polychromatophile. I enjoy having a caesar salad, but the oiley dressing gets on my tshirt, and then for the life of me I cannot find anything to get the oil stain out. I tried 1001 carpet cleaner, oxi clean, vanish stain remover and all manner of suggested ideas from the internet, but none of them work. I only have so many tshirts, so something has to be done sooner and later.