Using Hydrogen Peroxide in the ears to cure colds and the flu is based on the incorrect notion that the viruses enter the body through the ears. It makes no sense from a medical perspective for the following reasons:
1) The outer ear (the part from the ear drum outward) does not connect to the middle or inner ear in a normal person. It is a dead end in there just like your belly button. Your inner ear does drain into your throat, but that is separated from you outer ear by your middle ear and ear drum.
2) You catch a cold after a cold virus enters your nasal cavity through your nostrils or through your tear ducts. The primary vector is your hands.
3) Even if a virus could enter your nasal cavity through your ear, how would disinfecting your ear after the fact help stave off the infection of your nasal cavity? There is no ligical mechanism here. This makes a much sense as rinsing out your mouth to prevent a hangover after ingesting too much alcohol.
4) Any evidence that this works is anecdotal and explained by the placebo effect. Doing anything at the earliest signs of a cold can create an illusion of effectiveness because people don't always get sick after experiencing something like an early cold symptom. If you hopped on one foot at the earliest sighs of a cold, you would find that most of the time you didn't get the cold you were expecting. Is this due to hopping on one foot? Yes, absolutely, if you believe it is.
As for the Zinc lozenges, they are somewhat effective and this is supported by legitimate medical research. However, they are also subject to the effect mentioned in number 4 above. Their perceived effectiveness is greater than their actual effectiveness due to the placebo effect. Also, many people believe they have a cold when in fact they have something else (such as sinusitus) so a legitimate cold remedy would not work in those cases.
I would recommend trying zinc lozenges. I would also recommend vitamin C and ecinachea, although these have not been proven effective in any well-done studies. I would also recommend plenty of sleep, fluids and even chicken soup.
And remember the old adage that an untreated cold will last 2 weeks, while a treated cold can be beaten in as little as 14 days.
The main thing to remember is not to use a multi-symptom cold remedy such as Nyquil. These will just make you feel worse on the whole. Also avoid decongestant nasal sprays which can cause rebound congestion and addiction. For nasal congestion I like pseudoephedrine (read the label about heart conditions). For a sore throat, try gargling with warm salt water. Lozenges also help.
As for the flu. Just get a flu shot every year before flu season.