If they become aggressive towards you, this could be for two reasons as far as I know.
Either you didn't program them well enough or your will wasn't strong enough to properly program them to do as you command.
Or they have absorbed other influences, their energies becoming muddled and mixed with other energies. When that happens thoughtforms can change their behavior, or even turn against the creator due to getting influenced by those other energies they take in.
Thoughtforms are very sensitive to energy, to keep them clean and strong you should fill them with energy and with the affirmation and intent you used to create them at least once a week. This will reinforce their programming and overwrite any other influences or energies they might have absorbed.
If a thoughtform you create protects you from other thought forms for example, they get influenced ever so slightly by the energies from the other thoughtforms it encounters, eventually this can lead to them "forgetting" their original programming and intent as it get's overwritten by other energies.
Instead of destroying a thoughtform you can simply clean them and reprogram them, or even tell them to go to sleep untill you call upon them again.
They can remain dormant without loosing energy for weeks and even years. An SS friend of mine recently found a thoughtform they had made years ago again, out of nowhere. They had forgotten about it for years and not put any energy into it for all that time, but it came back and suddenly appeared years later, still functional after receiving cleaning and reprogramming.
Dousing them in water might not have destroyed them though, it might have just messed with their energies even more, you should see if you can still find them and then clean them, reprogram them and they should still be functional.
To destroy a thoughtform you can vibrate it's name in reverse and affirm it to be completely destroyed or you can affirm it's name followed by "you are no more." They will simply get destroyed then.
Bombarding them with energy usually doesn't destroy them as they are made of pure energy, it will simply mix with them and mess them up even more, potentially causing you even more trouble.