Jeep TJ Wrangler - No Heat Troubleshooting - Heater Core Flush

We continue our process toward fixing the heat in the shop TJ, first it was a bad heater control panel, now with that fixed the heat is lukewarm at best. So next step, flushing the heater core.

Tubing -
3/4 ID clear tubing at least 5'
https://amzn.to/3SAacAL

5/8 ID clear tubing at least 5'
https://amzn.to/3SAYxS8

Fittings - Barbed to Female Hose End Fitting
3/4 Barbed Fitting to Female Garden Hose End
https://amzn.to/42c4M2h

5/8 Barbed End to Female Garden Hose End
https://amzn.to/3ujT0WR