Dish soap or WD-40? I have been using dish soap to clean my chain from the start, since that's the only thing I can find I think suitable for cleaning oily stuff. I use two old tooth brush, grab a ziptie and tie it together with the brush facing each other and I scrub the chain and apply a good amount of dish soap. Is that method okay to use? If not, I will start using WD-40 as a degreaser because I can't find any other degreasers around my area and I can't shop online. So, do I just spray WD-40 on the chain and leave it there for awhile and start scrubbing or what?

Sadly, I think traditional wd40 has the edge on dish soap for the express purpose of removing grease and oil from a chain.

Dish soap/detergent needs water added to "activate", that is provide a carrier for the soap molecules to move through, and orientate their hydrophobic end into the grease/dirt. Without water the hydrophobic end has nothing to be scared of!

Personally I think a proper degreaser will be superior to both, but there's little point wanting on things you can't get.

On that note, dish soap is probably a lot cheaper than WD40. I would imagine blowing through a quarter of a can to clean a chain. You can buy the same stuff in bulk in a bottle rather than a pre-pressurised aerosol, which is intended for self-fill pressure sprayers or drip-lubrication on aluminium cutters.