I didn't see a section for lemons or lemon juice on blackheads so I wanted to contribute.
The acidic compounds found in lemon juice are amazing for breaking down oils and clearing up those embarrassing blackheads. I have been using the following remedy for about 3 days now and have noticed quite a difference in my complexion!
I take a warm shower (opens pores) every morning before work and every early evening. After shower, I push up on my nose from underneath to try and clear out as much loosened blackhead 'plugs' as possible.
I then apply lemon juice to a cotton ball and dab it on my nose and around the 'T-area'. It may sting a bit at first and direct sunlight should be avoided for about 30 minutes after applying.
This has netted me substantial results, although people with sensitive skin may have reactions to the nature of the acidity.