SQL & PL/SQL :: How To Retrieve Unique Values From A String

Objective: I need to compile a final string by concatinating the unique values from different strings.

Here is the script to create tables and data.

Create table temp_acronyms(id number, acronym varchar2(30);
insert into temp_acronyms values(1, 'ABC');
insert into temp_acronyms values(2, 'DEC//NOFO');
insert into temp_acronyms values(3, 'CBK//FO TO USA');
insert into temp_acronyms values(4, 'DEC//NO ENTRY');
insert into temp_acronyms values(5, 'ABC//NOFO');

COMMIT;

select * from temp_acronyms;

ID ACRONYM
--- --------
1 ABC
2 DEC//NOFO
3 CBK//FO TO USA
4 DEC//NO ENTRY
5 ABC//NOFO

I need to store all the unique strings from the acronyms for id's 1,2, 3, 4 and 5 into a variable. doesn't matter even if it is through database procedure.

my final string should have the values as below

ABC//DEC//NOFO//CBK//FO TO USA//NO ENTRY