Okay I need some advice here.. I've posted in here about the sand dollars I was trying to restore back to their natural color and I got some advice.  Well a couple weeks ago I did put them in 2 different plastic containers in a dark spot which is the shed in our backyard on a somewhat cooler day and proceeded to then pour the hydrogen peroxide in each plastic container and closed the shed door so it would be pitch nlack in there. 

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I checked on them after 48 hours and not much of a change so I decided to give it a couple more days.  I them stopped and rinsed them off in water like you're supposed to.  However one of them has turned a slight bit of yellow and I'm not sure why, and other's only a slight change... And so while the bottom of the sand dollars are definitely a bit better than the way they previously looked, definitely not the original color.  

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WHAT CAN I DO NOW??  Would bleach be recommended? And if so how long should I soak them in Bleach cauae I don't want to ruin any of these completely.  If you're going to recommend bleach then would it matter whether it was scented or not because right now we currently have scented bleach and I believe it's no splash... HELP!

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I'm sharing before pictures and then after hydrogen peroxide... 

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What can I do now??