I was cleaning my paint brush, bucket and roller in my bathtub. Afterwards I noticed that I stained a couple spots of the bathtub. The stains are a light blue (the paint was a dark blue). I am not sure of the material of the bathtub but it is the common material you see a lot of bathtubs in apartments (The closest thing I would relate it to is fiberglass with a white shiny glass but I don't know/think it is fiberglass). It isn't dried on paint (it feels completely smooth and looks like a stain).
How can I remove the stain? I have tried scrubbing, baking soda and water (paste), baking soda and hydrogen peroxide(paste), and bleach but I haven't got it off yet. I could try scrubbing harder but I am afraid of harming the tub itself.