As a mom of a very craftaholic little girl who has used walls, carpet and clothing as her canvases in the past, I know a thing or two about stain removal. In fact, I consider myself a stain removal expert. My top commercial stain removal products (in no particular order) are:
Biz Stain Activated Booster
Carbona Stain Devil
I’m sure there are a number of other excellent commercial stain removers on the market, but I tend to stick with ones that I have had good experiences with, and the aforementioned products have served me well over the years removing set-in stains from various items. I will note that some of them require modifying to get the most bang for your buck. For example, if you are trying to remove super set-in ink stains from cotton garments, then I would suggest mixing Biz Booster with boiling hot water. Once the Biz has dissolved, add in the ink stained garment and let it boil for about an hour. When the 60 minutes has elapsed, take the pot off the burner and allow the stained item to cool. The cooled garment should then be placed in the washing machine with the remainder of the Biz and water mixture and the garments should be cleaned per the washing instructions.
If you prefer using inexpensive homemade stain removers, then think outside of the box. For severely set-in stains consider sandpaper. It does wonders to remove set-in ink stains on suede and leather. Just use a strip of fine grain sandpaper to gently buff the stain before dipping a soft bristle toothbrush into white vinegar and lightly scrubbing at the affected area. The stain should lift, and then you can use a clean, dry toothbrush to fluff up the nap.