What is best to put on a bad scrape/laceration to stop it from seeping fluid (not blood)?

Pretty simple. Scrapes generally heal better if they are kept moist and clean. They will always exude a little serum (the liquid part of blood)-this is normal. I recommend washing them with soap and water 2-3 times/day and then applying a thin layer of Bacitracin ointment covered by a bandaid or gauze pad taped into place. The frequent washing is probably the most important manuever.
Antibiotic,dressing. Assuming it is a scrape and not infected a topical antibiotic with a bandage is appropriate. If it is swollen or painful you may need prescription antibiotics.