>>10559306Air dry clay and epoxy are ridiculously easy to use, they take at least 10 minutes to start drying, so you have more than enough time to fix your sculpt or remove the entire thing, and even after its completelly solid, if you're not happy with the results, you can remove the air dry clay just by washing it (I sealed mine with clear acylic paint after painting the whole face).
About yellowing, hasbro used better plastic on him, mine still pristine white after months while my Tigatron got random tan parts.