▁so aps ▁and ▁sc our ing ▁cre ams ▁in ▁general ▁composition ▁and ▁mode ▁of ▁action , ▁but ▁differ ▁somewhat ▁in ▁the ▁form ▁( d ry ▁pow der , ▁instead ▁of ▁a ▁bar ▁or ▁paste ) ▁and ▁in ▁the ▁primary ▁intended ▁applications . ▁ ▁Sc our ing ▁pow ders ▁comp ete ▁in ▁their ▁intended ▁uses ▁with ▁sc our ing ▁p ads ▁and ▁steel ▁w ool . ▁ ▁Com position ▁A ▁typical ▁sc our ing ▁pow der ▁consists ▁of ▁an ▁ins ol ub le ▁ab ras ive ▁pow der ▁( about ▁ 8 0 % ), ▁a ▁sol ub le ▁base ▁( 1 8 %) ▁and ▁a ▁d eter gent ▁( 2 %). ▁It ▁may ▁also ▁include ▁perf ume ▁and / or ▁a ▁dry ▁ble aching ▁agent . ▁ ▁The ▁ab ras ive ▁can ▁be ▁sil ica ▁( qu art z , ▁), ▁f eld s par ▁ ▁( such ▁as ▁orth oc l ase ), ▁p um ice , ▁ka olin ite , ▁soap stone , ▁tal c , ▁calci um ▁carbon ate ▁( lim estone , ▁ch alk ), ▁cal cite , ▁etc .. ▁The ▁particles ▁should ▁have ▁reason ably ▁uniform ▁size , ▁less ▁than ▁ 5 0 ▁ μ m ▁in ▁diameter . ▁Hard ▁ab ras ives ▁like ▁sil ica ▁and ▁p um ice ▁can ▁can ▁remove ▁t ough er ▁st ains ▁but ▁may ▁also ▁scratch ▁glass , ▁metal , ▁and ▁gla zed ▁cer am ics . ▁ ▁The ▁sol ub le ▁base ▁is ▁meant ▁to ▁break ▁down ▁fat ty ▁subst ances