Replace starting and ending characters of a string

Question

Hi, I have a string like 

string alpha = "\"1:1,2:4,3:6,4:13,5:19,6:20,7:24,8:28\""; and I want to get remove the starting and ending character, the required string is like 

string alpha = "1:1,2:4,3:6,4:13,5:19,6:20,7:24,8:28";

any favor will be appreciated.