Escaping quotes from post

in a textbox i enter this :

testing’s and “testing”

then when I retrieve it from POST i get this :

testing’s “testings”

Obviously I need to get rid of those slashes, so I try this

$emailMessage     = str_replace("\'","[]",$emailMessage);
$emailmessage     = str_replace("\"","[[]]",$emailMessage);

where later I can replace the [] and [[]] back with single and double quotes
it works with the single quotes , but not the double quotes… here’s what I get…

testing[]s “testings”

any ideas?