What is the best way to remove stickers from a plastered wall?

Bst12761662
by Bst12761662
The worst part is....the stickers were put on plain (no paint, no sizing) plastered walls in 1988. I have done nothing to the walls since all these stickers were put on. Now I want to paint the walls....how do I remove the stickers??
Thanks for anyone's input!
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