Old BB Gray Beige Vinyl 😱 Question

I have some cute very old BB kits that are the hard very gray beige vinyl. Wow-- they are not taking the paint, and neutralizing is unlike any other kit. For those of you who worked with the earliest BB kits- any tips? I am struggling.

How old exactly? There were some sort of muddy brown/grey ones few years back, and I found that best way to deal with them was to make them darker skinned babies. Unfortunately, some were skeeter fairies, which i wanted pale and fairy like, and the only way to get anything I was happy with was lots of white washes, and they often ended up bit streaky, and had to be wiped off and started again.

Terracotta washes work on them.