Stimulants will probably be in a similar condition to yours. Sticking with sackcloth insulation also makes no sense (photo). If you do not want to throw away the 280 PLN, buy the appropriate RPK heat-shrinkable T-shirt (the one with glue inside - for cable repairs, for forging in any electrical store) and stretch the appropriate section on this damaged pipe and heat it with a heat gun or over the gas cooker "take off" the T-shirt keeping the original shape of the pipe during this operation.
Before that, of course, wash well with the oil with a suitable degreaser (degreaser, breakclean, etc.)