Just like any other stain, the faster you treat blood, the more likely it is to come out of the carpet. However, if you're cleaning a fresh bloodstain, some extra steps and care must be taken, so it doesn't spread. Use a clean, light-colored cloth and blot at the stain, pressing down firmly and then lifting up quickly. You're aiming for a straight up-and-down motion. Work from the edges inward and avoid rubbing the stain at all.

It may sound counterintuitive, but it's actually helpful to add moisture to a fresh bloodstain in some cases. Be sure to use cold water, as warm or hot water can cause the stain to set in the carpet permanently. The key is to dampen the stain but not soak it, as too much water can cause it to spread. A spray bottle is best, but if you don't have one, use a cup and slowly pour out just a small amount of water.

Continue the process of blotting the stain, then moistening the carpet, and then blotting again, until the carpet is clean. Fair warning, it may take several rounds of this. It's a good idea to have a second blotting towel in case the first one gets too wet. Having a clean, dry towel is key to effectively getting both the stain and moisture out of the carpet. If you have a wet/dry vacuum, that can also be used to extract the moisture.

If your arms are tired from blotting and wetting and the bloodstain is still visible, it's time for another trick: salt paste. To make it, put some cool water in a bowl, then gradually add enough salt to make a paste. Pour a small amount directly over the stain and let it sit for ten minutes. Using a fresh towel, blot the area. If you can still see the stain, but the towel is picking it up, repeat the cycle.

Add a few squirts of liquid dish detergent to a bowl of cool water and stir. Take care to not use a soap that contains bleach. Dip a clean cloth or sponge into the mixture and apply it directly to the stain, using the same blotting technique you've been using. Spray the area with plain water to rinse the solution, then use another clean, dry cloth to blot it dry. Repeat this step if you see progress being made.

If dish detergent didn't work, try using ammonia. Similarly to dish soap, ammonia needs to be diluted to be used on carpet. Add a tablespoon to a half-cup of cool – not cold – water and mix. Using a clean sponge or cloth, apply the mixture directly to the stained area. Blot with a clean, dry towel until the moisture has been absorbed. Even if the stain appears to be gone, spray the area with plain water and blot dry.

Remember doing the experiment where you combined baking soda and vinegar to create a "volcano" in school? We're not doing exactly that, but the concept is similar. Combine a tablespoon of baking soda with two parts water and one part vinegar in a spray bottle. Just like in the experiment, it will fizz like crazy, which is why a spray bottle is best. Apply the formula to the stain, then be sure to blot completely dry. This is not something you want sitting on your carpet.

If the carpet is wet for too long, a whole new stain can appear – even if the original one has disappeared. This happens when blood remnants on the carpet's backing seep up to the surface or when discoloration from too much liquid creates a water stain. To prevent this, speed up the drying process. You can either use a fan pointed at the stained area or put paper towels directly on top of it, then weigh them down with books or another heavy object.

Once the carpet has dried, and the stain is no longer visible, you'll want to vacuum and brush it out to restore the carpet's fluffiness. All the added moisture and blotting have likely compressed the fibers, but it's an easy fix. Vacuum the area first, then use a toothbrush or soft-bristle hairbrush to gently brush the stained area, so the fibers stand upright, taking care not to pull or snag any of them.

Stains that have already dried are obviously going to be tougher to get out. Start by using a butter knife or a firm brush or toothbrush on the carpet's surface to loosen the dried fibers. While this won't remove the stain, it will help to separate the individual carpet fibers and make cleaning a lot easier.