Restoring floor boards with Por 15 kit. Remove "tar like" factory piece or not?

Re: Restoring floor boards with Por 15 kit. Remove "tar like" factory piece or not?

I sell POR15 at an auto parts store I work for part-time and my son and i have used over 2 gallons (in quarts cans) so far. Here is what I have learned about POR15.
1. You do not need the Marine Clean, unless you need to remove oil or grease.
2. After removing sound deadening material (its not for strength), cut rusted steel away to good metal, remove any burrs and scuff floor pan (I use a DA with 120 grit paper) where POR15 will go.
3. Use Metal Ready on all bare metal (I use it under regular paint too) and if caught in a pan, just pour it back into bottle and reuse it until it is gone. Keep bare metal moist with Metal Ready for 1/2 hour, rinse with water and let dry overnight. Heat gun can be used to dry faster.
4. After floor is dry, cut fiberglass to fit floor and set aside.
5. Put gloves on hands (if it gets on skin, you wear it for about 2 weeks. A guy into the store who had sprayed it and had black freckles on his face ), open can of POR15, stir (do not shake) and paint floor.
6. Put plastic wrap over open can (cover will not come off if plastic wrap is not used and Walmart bags work great) and tap on cover.
7. After a 2 hour set time, paint bottom of fiberglass, position onto floor, cover can with clean plastic wrap and tap on cover.
8. Again after a 2 hour set time, cover fiberglass with a good coating of POR15 and paint under side of car.
8. Finally cover open can with clean plastic wrap, tap on cover and store can upside down. The reason for storing upside down is because air is trapped inside can and after a few days, paint will skin over and get thicker with storage time. Some guys I have talked have pushed plastic wrap down inside can, so it is on top of paint and they say it does not skin over this way.