What is the easiest way to grind combat EXP? My CMBT level is 132, and I have 70 Atk, 60 Str, and 61 Def (I am a member)
It honestly depends. You will need to find a monster with relatively high hit points. Find its weakness (ie; Bolts or something) and then get geared up. Attack it and if you are getting completely owned, it is not a good spot. You want to find monsters that are relatively weak.
It also depends on whether or not you are a member.
Maybe go for something like ogres or rock crabs at your level.
Rock Crabs: Level: 102 HP: 2550 EXP: 243 Weak To Water Spells Ogre: Level: 80 HP: 2000 EXP: 145 Weak to Magic
It should be noted that although these monsters are weak to magic, they are also relatively weak to melee and exp can still be gained at a considerable rate.
You could also do slayer tasks. https://runescape.wiki/w/Pay-to-play_melee_training
Train on black demons or steel dragons in Karajama dungeon. Steel dragons give 987 exp. Naturally, one third goes to contstitution. Black demons spawn much faster and give 867 exp. Same rule applies for constitution, but steel dragons drop better loot. It's not too hard of a decision as they're only separated by a doorway. An easy way to get to 99 attack, defence, ranged or strength, but it still takes a while.
If you have high enough summoning, bring a war tortoise and save the infernal ashes from the black demons. A full (yours and tortoise's combined) inventory of infernal ashes is an easy 200k for each trip to the GE, and an easy 1M per hour. Depending on how fast you are, you could even get 3M per hour.
If you want to train on steel dragons, they drop dragon bones, which are worth 4.6k each, steel bars (worth 1.3k each) and commonly runite limbs, which are worth 9.8k each. Assuming they all drop runite limbs, its an easy 9M per hour as long as you have the war tortoise with you. If you have the pack yak, you can make up to 28M per hour. Though, steel dragons don't respawn as fast and the place that they are in only has about three of them, however, if no-one else is around, it's a really quick way to get rich.
The only thing that could put you off is the summoning part but no worries. Even without the summoning you can get rich. It may take a bit longer, but its easier, and if you have enough mining, mine rune ore 10k each. For a full player inventory, each trip to GE is an easy 20M per hour. Hope this helps. :) Have fun.