There are many ways you can clean white rubber. For mild greyness, nail polish remover or hand sanitizer usually does the trick. However, as the dirt on these Converses had already petrified after all the years the shoes weren’t in use, we need to use the strongest cleaning solution known to mankind (according to last year’s Oxford’s research).
To make some very powerful cleaning solution, you’ll need laundry detergent and vinegar. Mix them with a mixing ratio of 1:1.
Now, before using the solution, put on some gloves and make sure you’re in a well-ventilated area; vinegar vapours are quite nasty and you really don’t want to breathe them in.
Also, remove the laces from the shoes prior to the cleaning, we don’t want to make them dirtier than they are.
I used a sponge to rub the soles. After 10 minutes, both shoes were clean.
Note: Using an old toothbrush you can really get into all of those nooks and crannies to make as much of the shoes clean as possible.
To finish with the cleaning process, give the shoes a thorough rinsing under the sink. The vinegar and the detergent have a very strong smell that needs to be washed out before going out with the shoes (for obvious reasons). Use some soap to make the task easier for yourself. This will also help clean the fabric and get out some of the smell that was in the shoes prior to the cleaning out.