Help with merging nonblank cells into a single string

[ThePurleyKing]

Hi Everyone,

I am collecting Panini 2012 stickers
I have created a spreadsheet which shows which stickers I need and which I have doubles of. Ideally I'd like to be able to merge the cells containing numbers of the stickers I need into a single string and the ones I have doubles of into a different string (i.e. 34, 56, 79, 123, 134, 156 etc etc). The relevant data is in columns H and I and I need to remove the blank cells.
I've attached the sheet I've created here - can anyone help? I've never used macros before, but suspect I might need one here?
Thanks in advance!
Jim