I don't see a difference between Gen 9:4, 5 and Lev 17:14. I think I get what you are saying, you can never FULLY drain blood right? Watchtower has addressed that line of reasoning though. I don't remember where, but I remember reading it.
The text of Leviticus 17:14 is a prohibition stated of eating blood of any sort of flesh.
The text of Genesis 9:4 is a prohibition stated of eating blood obtained from one sort of flesh, that of living animals killed to use as food. Another sort of blood the text of Genesis 9 never mentions or addresses is that of animal carcasses dead of natural cause. Nothing in the text of Genesis 9 prohibited Noah from eating all the blood he wanted from that sort of flesh, which was then and always had been readily available and safer to obtain and use as food for the ancients.
There's another critical difference too between Leviticus 17 and the text of Genesis 9. Leviticus 17:13 stipulates that blood obtained from killing animals had to be disposed of by pouring it into the dirt (this speaks of animals killed other than those used for sacrifices). Nothing whatsoever in the text of Genesis 9 required Noah to waste perfectly good blood by throwing it away into the dirt. Noah was free to do whatever he wanted with blood he drained from animals he killed to eat, so long as he did not eat it.
By the way, nothing I've said or presented requires any special measures in relation to bleeding other than general bleeding of animals killed to eat. There will always be residual blood left in flesh.