Fresh fruits, nuts, vegetables definately.
The way I see it, look on the back of a packet of bread and there may be more than 50-60 ingridients! So I don't touch it. If, however you have a potato, often there is no packet to look on, and it is alive. Better to eat boiled potatoes than bread (at least the bread that you buy in the supermarket). I have made my own Ital bread, but it is time consuming to do yourself. Better to have brown rice than supermarket bread, too. And Barley.
I would suggest doing this for more than a few days; you need to make it the way that you live long term.
All fruits, vegetables will detox you. However, here are some of my all time favourites;
Raw onions (also can be made into a juice)
Raw Garlic (and above taken as part of a meal)
Beetroot (a star in terms of detoxification). Can be made into juice.
Aloe Vera leaves (must be the whole leaves)
Citrus juice (particularly lemon, taken as part of a juice, and lime) Orange juice too.
Radishes (great detox weapon)
Celery and Cucumber juice (cooling and cleansing)
Dandelion flowers/leaves. Where I live, they grow wild so you can forage.
Wheatgrass juice. Grow your own. Takes less than a week from seed to crop. (buy seeds online) and blend the blades of grass in water, and strain through tights. Doesn't work in my juicer for some reason, so use method as stated.
Now, don't have all the above at once, else I fear that we will not see you on the forums for.... a long time.
All the best,