Some public attitudes are stubborn and hard to shift. Think prejudice against women, immigrants, gay people and those with disabilities. Years of legislation and commissions, and still these prejudices are irrationally with us.
Others, though, respond faster. The Government's campaign to reverse negative perceptions of teaching - strapline: 'Those who can, teach' - has been so successful that in some disciplines we've more job seekers than classroom vacancies.
I'd like to take the teachers campaign as the basis for a drive to find more and more varied trustees to get involved with our charities. The Charity Commission has, for some time now, been trying to tackle the perceived bias on trustee bodies towards elderly, white, middle class males.
Some donors have introduced quotas: unless half the trustee board of a disability charity, say, consists of disabled people, there can be no grants.
And a debate is now raging about whether trustees should be paid. I'm against. To professionalise the trustee class would be to take away one of its main strengths - the spirit of giving something back to the community because you care.
But I do acknowledge the need to find a new generation of trustees. So why not advertise - not just for specific vacancies, but about the joys of the role? Why not 'Those who can, trustee'?
There are several myths that can instantly be exploded. First, that you have to be great or good to be a trustee. I've always found the ' big names' much more likely to miss meetings. What we want is honest, well-intentioned, ordinary folk, the sort who feel that any volunteering they do has to be restricted to a few hours once a week in a charity shop.
There should be no glass ceilings in our world.
Second, there is the fear that you will carry the financial can if it all goes wrong. Such episodes are rare. Most charities build in to the trust deed a limit of £1 on trustees' personal liability. Third, and most of all, there is the perception that you have to have a special expertise to be a trustee. Professional skills help, but the most important qualities are enthusiasm and common sense.
An advertising agency could be persuaded to give its skills gratis. Broadcasters might even be cajoled into making airtime available. And we might find that the 'crisis' in trustee recruitment eases once the message that all are welcome gets an airing.
• Peter Stanford is a writer and broadcaster, chairman of Aspire and director of the Frank Longford Charitable Trust.