Most of my materials come from curb side rubbish collection piles - so there is no shortage of old mops to choose from.
And yeah - improvised tool use is one of my specialties - Just yesterday I was faced with getting some huge sturdy card boxes into the bin - the stanley knife was breaking my balls - Cordless Jigsaw made short work of it
Cut out the shape you want with a dremel or angle grinder - then blast with the heat gun until it gets floppy - then shape with gloved hands - hold it in place and run cold water over it to set quick and you're done