Quote from: laur_dinu on January 12, 2018, 08:19:52 AM

It is my understanding that if I no longer sync that wallet I will not broadcast the transactions and in 20 days ( Bitcoin Core ) will be drop from all memory pools so my BTC will 'return' to source .

That's not enough, Bitcoin Core will just re-broadcast it again when you start it.

Quote

What can I do ? The best solution for me is to drop the transactions and 'return' the bitcoins to the source wallet .

You can manually remove the transactions from Bitcoin Core:
-Exit Bitcoin Core
-Backup your wallet.dat, even though you should have a backup already, make another backup
-Start Bitcoin Core from a command prompt with options -zapwallettxes -rescan (if you're using a pruned wallet, you can't use this)

Depending on your hardware, it will take a few hours to rescan. After this, your transactions should be gone, but Bitcoin Core might pick them up from mempool again. In that case just wait for it to drop again.

Full description of the commands:

Code:

-zapwallettxes=
   Delete all wallet transactions and only recover those parts of the
   blockchain through -rescan on startup (1 = keep tx meta data e.g.
   account owner and payment request information, 2 = drop tx meta
   data)

Code:

-rescan
Rescan the block chain for missing wallet transactions on startup

Another tip: don't use inputs like this one:

Code:

17h6vyHcZee6VAxeTvgbhALFvbzZpv9KC9 (0.00000001 BTC - Output)

It's Bitcoin dust, and costs you a lot more in fees than it's worth. If you Enable coin control features (click Settings > Options > Wallet), you can manually select which Inputs to use when you make a transaction. Don't use these very small inputs.

One last thing:
You also own Bitcoin Cash, Bitcoin Gold and Bitcore! If you didn't know this yet: it's worth about $700 in total. After moving your Bitcoins, I can explain how to claim it if needed.