remove single quotes and ' , ' from the end of string in Salesforce trigger?

Here is the Sample code which you can use to remove the ',' if there is any at the end of your string.
string teststring = 'Myteststring,' ;
if(teststring.endsWith(','))

{teststring= teststring.substring(0,teststring.length()-1);
system.debug('@@@' + teststring);
}