Here is some old time scent tricks before the modern smelly sticky formulas in a bottle.  Many of the commercial scent jellies and pastes are outstanding attractants.

Vaseline Balls

This is a old time bait substitute. 

• remains from making egg clusters sand shrimp head (Optional)
• orange, red or yellow sponge balls (cut up a sponge into bait size pieces)
• coffee can
• Vaseline

1. In coffee can melt Vaseline (unscented) on low heat.
2. take leftovers from egg clusters and sand shrimp heads and add to melted Vaseline ( or  use a commercial scent oil)
3. stir until smooth as possible 
4. add more Vaseline if it gets to thick
5. Add  sponge balls 
6. squeeze balls until they are saturated with the mixture.
7. remove and place balls in Ziploc baggie
8. freeze for freshness

Scented Jelly paste

Place spoonful of Vaseline in film container and melt in microwave. Now add scented oil of choice and stir.  Chill to setup mixture. Seal container and go fishing with your new scent . When using fresh bait remember to keep it cold when not in use.

If you have access to a freeze drying system you can preserve your bait with out the need for refrigeration. This will make for some really concentrated scents.