Crap in, crap out ... Worm castings (dung for all practical purposes) are rich in chitinase, and it is all natural! This link is an example of a liquid product - whole bottle for $13.95 You would need to sanitize as a final step. The worms eat cow dung to produce their primo bug dissolving poop. If you are averse to this, study how you may be able to extract chitinase from plant matter. Wikipedia states "Chitinases occur naturally in many common foods. Bananas, chestnuts, kiwis, avocados, papaya, and tomatoes, for example, all contain significant levels of chitinase, as defense against fungal and invertebrate attack." You may be able to make a do it yourself crude extract considering the reported method by Sanchez-Monge et al (Clinical and Experimental Allergy,1999, Volume 29, pages 673–680) is as follows:
"Canary banana (Musa paradisiaca L., an hybrid of M. acuminata Colla M. balbisiana Colla) fruits were peeled, cut in short pieces, freeze-dried, ground in a mortar with cold acetone, and then defatted with the same solvent (3x, 1 : 5 (w/v); 1 h; 48 C). The dried residue was extracted with PBS buffer (0.1 M sodium phosphate, pH 7.0, 0.15 M NaCl; 1x; 1 : 5 (w/v); 1 h; 48 C), and after centrifugation, the supernatant was dialysed against H2O and freeze-dried(crude extract). Alternatively, the PBS-extracted supernatant was brought to pH 3.5 by addition of 0.1 M HCl to obtain a protein preparation enriched in chitinases . After centrifugation, the supernatant of the acidic treatment was dialysed against H2O and freeze-dried." Be careful with acidification. Acid may react with metal. A do it yourself pH test can be done with red cabbage juice.
Your can may be able to osmotically chip at him. Ethanol will dehydrate the tissue. Then water will swell the tissue. Repeat the cycle. This will also extract lipids.
Only molecules left would be proteins. Other posts talk about proteases. But at this point detergent should liberate proteins.