A scuffed, dusty gem of a show, Squeeze Box is that rare solo performance that transcends its own idiosyncrasies. Marble-mouthed comic Ann Randolph (plucked from obscurity by producer Anne Bancroft) mines her experiences working the graveyard shift at an L.A. shelter for insights into, yes, herself. Luckily, it doesn't end there. Randolph weaves ruminations on faith with pungent impressions of, among others, a schizophrenic prostitute and an accordion-playing lover -- yet never devolves into therapy. The ''self'' Randolph sings is almost Whitmanesque, and if her conclusions amount to little more than a nostalgic ache for sepia-toned New Deal-era idealism, what of it? It's revolutionary enough to hear her discuss toe sucking so reverently, you'd think she learned at the feet of Buddha.