Here's another trick an audio editor told me about: cut out the desired section of audio and run it backwards. It fits like a glove, you still hear the speaker's voice, but you can't understand what the speaker is saying.
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
[Dave LaRonde]"you still hear the speaker's voice, but you can't understand what the speaker is saying."
The odd thing is, "bleeping" actually draws attention to the fact that you're censoring some word. Most people know what that word probably is, so they "hear" it in their heads, anyway.
Another practice, simply dropping out the audio & leaving dead space, is a little less distracting, but it sounds like a mistake,and anyone who's attentive will, again, hear the censored word in their head.
Dave's practice of reversing the censored word is the least obtrusive, and the most likely to really bury and obscure it.