Regarding drawing blood into the snorkel, you can clean the snorkel itself fairly easily by removing the cap from the back of the unit and the rubber plug at the back of the snorkel. You can also replace the hoses inside. However, your will notice that liquid does run through and drain out of the unit.
The greater concern is the hardening of the meat proteins in the lines. With the unit resting flat end of the snorkel down, a little careful application of hydrogen peroxide from the opening at the back of the snorkel will loosen anything that has hardened and is blocking the suction. You may have to break up the pieces at the flat tip end with a narrow blade.
Also, please remember that our vacuum sealer supplier, Sealer Sales, Inc. (877-705-0203) has parts and technical advice available. They’ve been in the business since 1978, so have the expertise to give great answers.