Sulfuric acid is a colorless, odorless, and syrupy liquid.
Coloration indicates contamination, it could be from the storage container or the cap, some people report discoloration of H2SO4 when stored in polyethylene containers in elevated temperature.
It could possibly be organic/inorganic/metal contamination. Technical grade H2S04 is not pure and it's not colorless. Where did you get the acid from? Is it homemade? Some people purify drain cleaners containing H2SO4, to obtain it, because it is a watched chemical in some places. Improper cleaning of the drain cleaner can be the reason for the color.
NOTE: Don't do this if you don't have the appropriate facilities, equipment and knowledge, you can seriously injure yourself.
If you need small amounts of H2SO4 you can consider making it yourself (on small scale).
You can bubble sulfur dioxide in hydrogen peroxide or even better nitric acid and then concentrate the solution. Nitric acid is better option because it forms nitrogen dioxide, when no more NO2 is formed the reaction is completed, hydrogen peroxide dont indicate completion but its safer.
Sulfur dioxide can be generated by burning sulfur or with sodium metabisulfite and HCL.
DO THIS ONLY IN FUME HOOD!
Personally i wouldn't use it, atleast until i clean it.
Wait for more responses and opinions!
Good Luck :thumb_up: