Delete data in delimited string

[Garrett Hylltun]

Greetings,

How do I delete one field of data from a delimited string?  Such as:

item 1,item 2, item 3, item 4

And I want to delete "item 3" from the delimited string so that I end  
up with:

item 1,item 2, item 4


Thanks,
-Garrett