To be honest I don't think trying to mask a smell is the solution.
Better to work out what is causing it and deal with it that way.
Are there particular parts of your cage that get smelly?
What bedding do you use?
How big is your cage and how many pigs do you have?
Maybe we can help come up with a better solution for you.
My top tip would be to have large plastic hay trays lined with newspaper and huge piles of hay. Piggies spend a lot of time in them, and so a lot of wee and poop ends up there making it easy to clean them as often as needed.