I love cilantro and parsley (and arugala, etc) - so if I am at the supermarket and am in the mood - I can go overboard - and you are right - it goes bad quite quickly. I have a great idea for you - put bunches and bunches of cilantro (or parsley) in the food processor with a head of garlic (peeled of course) and a tsp of paprika and cumin - some salt and then start processing - adding olive oil until it becomes a sauce and then you can freeze it - and use it a bit at a time. You can do the same thing with hot peppers - (same spices) - and add a tsp at a time in your cooking.