For that, I would use a function with PATINDEX to retain only the desired chars.
If performance is not an issue, you can use a scalar function.
I can give you a sample function if you would like. I wrote somewhat similar functions to do "remove all non-alpha, non-numeric" chars and duplicate Oracle's "InitCap" function (first letter of each word is upper case, remaining letters of same word are all lower case).
SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".