How do i remove older poster mounds from the wall? i'm painting my room so i am currently preparing the walls to...

i'm painting my room so i am currently preparing the walls to paint. when i took adjectives of my posters off the walls, some of the poster mounds (very sticky white squares) are stuck on the wall still and i enjoy no idea how to go and get them off. they hold been in that for years so they're probably stuck on the wall pretty good.

also, how would i acquire old cartridge off the wall that's be there for years as economically?

thanks!
For a deck that is to say 50ft...
Answers:    use a sharp scraper to whip off the mounds afterwards if you have tarnished the wall fill near a fine smooth plaster or filler then sand around the nouns to blend in
same go for the tape remove stuff then sand