Chest looting is interesting. Here are some tips.
Take care when thieving from chest, or the hidden traps will hurt you. To avoid the traps, just right click on the chest and select “search for traps”, then the trap can be found.
If your cheap runescape accounts Thieving level is high enough, you can even disarm the trap. Usually, chests do not give you much experience, except for the Blood rune chest, which produces a great amount of profit.
While, I would rather spend most time on Pyramid Plunder, where you can find a gold chest in each room. It is also the best and fastest way to train your thieving skill, especially at higher levels.
Hope it helps, enjoy your gaming time!