You could try vinegar (as mentioned) or lemon juice both are acidic.
Mix a little baking soda and peroxide make a paste, you don’t need much. Then scrub this paste into the vinegar directly on the stain it should foam up a little from the reaction.
Could also try the paste and add some Dawn liquid soap (or similar).
A sacrificial toothbrush works for scrubbing.
Good luck.
Bleach maybe, but this has other dangers so be careful with that. You don’t want to spill bleach on the rug or clothes.
And never mix bleach with anything else.