How can a SIGNIFICANT AMOUNT of onion juice be obtained?
Initially, this seemed a logical question... yet, notice this healthy, freshly-sliced onion. What you are seeing is pure onion juice. Of course, not every onion will be as fresh and as tender and as healthy, but it hints at juice beyond.
So, for small amounts of juice, simply grate and sieve a portion of the onion. (Actually, some people prefer using their garlic presses.)
Remember: Onion juice soothes earaches; onion juice is a natural insect repellent; onion juice kills fungus; onion juice acts as an antiseptic for cuts and helps reduce bleeding; onion juice kills scalp bacteria and nourishes hair roots... and these are only thought-starters!
For larger amounts of juice, blenders or mini food processors are quite helpful.
Let's say a group of individuals gather for an onion scalp conditioning party. Hopefully one of them owns a juicer!
Depending on the situation, your onion PULP may be used in a manner similar to how you use your onion JUICE. For example, if you apply juice to a minor burn, why not then further soothe the area with pulp. Or, practice the mouth cleansing idea. Or, make onion muffins!