The 71-year-old singer-and-actress put around 500 items under the hammer earlier this month - including the iconic leather outfit she wore in the 'Grease' finale, which raised $405,700 - and she was stunned the souvenirs did so well as they had just been stored away gathering dust for a long time.
She said: "They were stored in cardboard boxes in storage rooms for many, many years.
"And some of them I hadn't seen for a really long time. It was such a surprise."
Olivia is currently battling breast cancer for a third time and though she regards every day as a "gift" after it spread to the base of her spine - causing a fracture which ultimately led to her needing to learn to walk again - she is staying positive.
She told the Daily Mirror newspaper: "There was a lot of concern but I was like, 'Yes, I'm going to do this'.
"It is hard and I still have one foot that will always, most likely, be a problem but there's no complaining.
"Every day is a gift but you realise that even more when you've been on a difficult journey."
To combat her pain, the 'Physical' singer takes drops of cannabis produced by her husband John Easterling and she thinks the drug has "really helped".
She said: "He makes me a mixture of 20 strains that he's grown specifically for me and it's really helped me. I mean I'm doing fantastic.
"I just take it on my tongue and it works really well, taking about an hour to go through your system.
"You have to go very slowly because it's a strong medicine, but John always says to me the feeling is the healing. So, I have to always remember that.
"But I've trained my body to accept more of it and it's obviously working."