This can be used to remove or save any range of characters from a string or field.

declare @s varchar(100), @i int

select @s = 'asd i/.,<>as>[{}]vnbv'
select @s

	select @i = patindex('%[^a-zA-Z0-9 ]%', @s)
	while @i > 0
	begin
		select @s = replace(@s, substring(@s, @i, 1), '')
		select @i = patindex('%[^a-zA-Z0-9 ]%', @s)
	end

select @s


gives
before
	asd i/.,<>as>[{}]vnbv
after
	asd iasvnbv


Removing the characters from a field in a table


create table #a (s varchar(100))

insert #a (s) select 'asd i/.,<>as>[{}]vnbv'
insert #a (s) select 'aaa'
insert #a (s) select '123 ''h 9)'

select * from #a

	while @@rowcount > 0
		update 	#a
		set	s = replace(s, substring(s, patindex('%[^a-zA-Z0-9 ]%', s), 1), '')
		where	patindex('%[^a-zA-Z0-9 ]%', s) <> 0

select * from #a

Gives

before
	asd i/.,<>as>[{}]vnbv
	aaa
	123 'h 9)
after
	asd iasvnbv
	aaa
	123 h 9