A.
If the residue dangerous goods cannot be removed from the ”Hoses contaminated with fuel” and “Containers with a fuel smell”, they remain as dangerous goods and the PSN by which they were received must be used for exit. For instance, UN3363 Dangerous Goods in Apparatus should be used.

As stated in DGR 7.1.4.5.1 Marking on Empty Packagings, 7.2.3.1.1 Labelling on Empty Packagings, and in the latter part of 9.4.3 Contaminated Baggage or Cargo Handling, steps such as cleaning, purging of vapors or refilling with non-dangerous goods must be taken to nullify any hazard. Unless these measures are taken, you must not remove the markings, labels and must not be transported by air. Unless a complete process of nullifying any identified hazard, the equipment cannot be regarded as non-dangerous article.